# Hourglass sources associated with spiral galaxies

• by raynorris scientist

Keep an eye out for any #hourglass sources that seem to be hosted by galaxies that look spiral in the infrared. These objects are incredibly rare in the local Universe (only 2 or 3 known) and we may not see any in Radio Galaxy Zoo, but if someone does find one, that would be worth writing a paper about (with the discoverer as co-author, of course). The rarity of radio-loud spirals is thought to be because the radio jets heat up and disrupt the gas in the spiral, switching off star formation, and turning the galaxy into a "red dead" elliptical. But we might find one or two where the jets have only just switched on and haven't yet destroyed the spiral. See http://adsabs.harvard.edu/abs/2012MNRAS.422.1453N for another example of this process in its very early stage. So keep your eyes peeled and yell out (very loudly) if you find one!

Posted

• These objects are incredibly rare in the local Universe (only 2 or 3 known)

Is it known why AGNs in spirals do not produce radio (and IR/optical/x-ray/...) jets and lobes?

What are the two or three (exceedingly rare) exceptions?

Posted

• Is ARG00000z8 what you're referring to? The top Radio contour appears to be associated with an IR source with a single spiral arm. I know we're looking specifically for an hourglass shape in the Radio, but this could be a vertical view of the houglass?

Thanks!

Posted

• by enno.middelberg scientist, translator

In this specific source I don't see a spiral galaxy, it appears that several faint IR sources are located close together.

Posted

• by JeanTate

Posted

• by JeanTate

And for the encore, a second one from infobservador ... this time much clearer (a jet+lobe coming from the nucleus of a spiral well into a major merger): The IR source is like a cross

Posted

• by Tobend

ARG0003eg7 looks like a tilted spiral or barred spiral and seemingly has a strong radio emission from the centre unless it's a very fortuitous alignment.

Posted

• Quite a few spirals - edge-on or not - with a central (nuclear/in the bulge) radio source have been posted here in Talk (and more in the comments on the images themselves, no doubt). A radio-active (not radioactive!) nucleus for a spiral is not unusual; many Seyfert galaxies have radio-active nuclei, for example.

Here's that inclined spiral:

It's IC 0634, UGC 05811 (and a bazillion other names!), with a spectroscopic redshift of 0.0276 (according to NED). It's one of the galaxies written up in Condon+ 2002, "RADIO SOURCES AND STAR FORMATION IN THE LOCAL UNIVERSE"

Posted

• Friday, 21 February, 2014: Very Strange Spirals? is an OOTD (Object of the Day) I just posted in the Galaxy Zoo forum.

In it I posted SDSS images of four galaxies which RGZ zooites have found to be associated with radio structures that are more than just nuclear, perhaps jet(s) and/or lobe(s); "found" as in posted here in a Talk thread.

I'm sure there are more, but I grew so frustrated with my inability to find things here, efficiently and effectively, that I gave up looking after a couple of hours.

Normally I'd post composite images - SDSS and FIRST overlaid, for example - but failed in this case, because I discovered I do not know how to do this, quickly and easily. Anyone?

Posted

• This was one found by antikodon that I remembered HAndernach commented on:

Posted

• Nice! Thanks! 😃

I'll write a new post in my OOTD, with these details (unless you'd rather do it yourself ...).

Does anyone reading this post know of any other examples of spiral galaxies associated with non-nuclear radio sources, particularly jet(s) and/or lobe(s), which have been posted/noted here, in RGZ?

Posted

• Here is one candidate that you flagged up some time ago now:

The object itself is in:

Posted

• How could we forget the elephant (sea horse) in the room (Universe)?

One previously known case (NGC 3079) has also turned up:

Posted

• Thanks WizardHowl.

I've already posted the first one in the GZ forum thread; I'll follow up with the others later this weekend (again, unless you'd rather do it).

Posted

• I made two composites of this, both written up in my GZ forum "Very Strange Spirals?" OOTD:

Posted

• by JeanTate

Not an hourglass, but complex radio emission that may be associated with a low-z interacting group, most of whose members are spirals; ARG0003jjg (mentioned by shaqua here)

Posted

• The hourglass emission from this edge-on disk galaxy is not the largest of radio sources but that also means it is clearer that it is the origin (although a background source can never be ruled out except by higher resolution observations, as per the usual caveat). The galaxy is SDSS J080259.73+115709.7 Z_ph~0.13-0.14.

The shape of the disk seems slightly distorted or bent and there is an odd colouration to the nucleus. I would be hesitant to rule out star formation as the source but that would need further imaging to say whether it was coincident with the radio.

Posted

• by JeanTate

ARG0000css (host is SDSS J102733.29+544227.9, z_ph ~0.25) reported by WizardHowl as possible Voorwerp (Voorwerp next to radio galaxy?):

Posted

• by zutopian

New paper:

Mega parsec relativistic jets launched from an accreting supermassive blackhole in an extreme spiral galaxy

Here we present the discovery of giant radio source J2345-0449 (z=0.0755), a clear and extremely rare counter example where relativistic jets are ejected from a luminous and massive spiral galaxy on scale of ~1.6 Mpc, the largest known so far.

Joydeep Bagchi, Vivek M., Vinu Vikram, Ananda Hota, Biju K.G., S. K. Sirothia, Raghunathan Srianand, Gopal-Krishna, Joe Jacob
(Submitted on 28 Apr 2014 (v1), last revised 29 Apr 2014 (this version, v2))
http://arxiv.org/abs/1404.6889

Is a Radio Zoo image of the galaxy available?

In the paper there is shown an SDSS image and the coordinates are given as follows.:
"the nucleus of the spiral galaxy at right ascension: 23h 45m 32.71s, declination: −04◦ 49′ 25.32′′ (J2000)"

http://skyserver.sdss3.org/dr10/en/tools/explore/summary.aspx?id=1237680117958246500

Posted

• I don't know how to get the RGZ number but if you go to http://skyview.gsfc.nasa.gov/current/cgi/query.pl and give it the co-ordinates you'll see that FIRST only shows emission very close to the galaxy, perhaps only the AGN, but that NVSS clearly shows long lobes.

Posted

• by JeanTate

ARG00012kb, as noted by zutopian: "#disc #spiral B3 0911+418
http://skyserver.sdss3.org/public/en/tools/explore/summary.aspx?id=1237657628978053334":

Looks like a faint radio core, coinciding with the nucleus of the galaxy, and two lobes, the N one of which has a complex morphology (including a jet).

The galaxy has a spectroscopic redshift of 0.140, a dusty spectrum classed as BRAODLINE AGN, a prominent dustlane, and features like a late-stage merger. Rather like Cen A.

Posted

• by JeanTate

ARG0000qmw, which I just posted. SDSS J101536.14+472044.1 (DR7 ObjId 588013382198297215) - not a photometric object in DR10.

<>

Galaxy has a non-elliptical shape, and a (DR7) photometric redshift of ~0.2. It is slightly to the S of the midpoint between the two radio lobes.

Posted

• Just encountered a clear disk galaxy with what appears to be very small lobes or jets emerging at right angles to the disk plane: http://radiotalk.galaxyzoo.org/#/subjects/ARG0002g0s

This may not be the largest or most powerful radio source but the radio emission is not compact. The galaxy looks like it could well be a spiral with either a tidal tail or long spiral arm extended due N. The host is SDSS J130140.93+183104.9 Z_sp=0.146 with a spectrum classed as starforming and showing strong emission.

Posted

• by raynorris scientist

Hi guys

I'm feeling so bad - I've been totally tied up with boring admin stuff and havent been on to Radio Zoo for months. can someone fill me in on what's happening with the hourgalss sources in spirals? How many do we have now? Is anybody going to write a apper on this stuff- they should! This is amazing stuff!
Ray

Posted

• Great to have you back, Ray! 😃

can someone fill me in on what's happening with the hourgalss sources in spirals?

I have made some half-hearted attempts to at least collect every field (ARG ID) related to any such candidates ('Spirals' with a jet (or jets) and/or a lobe (or lobes)), based on what I myself have found and what others have reported. I intended (and still intend) to produce 'triple composites' for each good candidate, like those I posted in the GZ forum thread Friday, 21 February, 2014: Very Strange Spirals? Here's an example (ARG00036hs, found by antikodon):

How many do we have now?

No one is keeping track (as far as I know); my guess is ~a dozen.

Is anybody going to write a apper on this stuff- they should! This is amazing stuff!

If any of us ordinary zooites knew how, I expect at least a couple would try (to write a paper on this amazing stuff)! 😄

Posted

• by zutopian

Discussion: An impossible source:

Posted

• by JeanTate

ARG00018d0, spotted by zutopian:

Hard to say with any certainty (I'll try to do a more detailed analysis later), but the obvious doublelobe seems to be centered on the edge-on disk galaxy, SDSS J164652.71+383845.3 (z_ph 0.156±0.133, 0.253±0.225):

ETA: Using Aladin on my Windows laptop, SDSS9 with FIRST contours:

The host may be the faint smudge, SDSS J164652.14+383839.9, and the alignment with the edge-on disk galaxy mere chance:

Posted

• by JeanTate

In the thread spiral galaxy with doublelobe emission, the following were noted as possible disk galaxies possibly associated with lobe(s)/jet(s):

• ARG0001zj8 SDSS J122640.22+253855.5 0.134sp excellent
• ARG0003qg8 SDSS J112526.53+014301.5 0.434sp too far away
• ARG00007yo SDSS J083136.46+574545.9 0.726 too far away
• ARG00027yg SDSS J170525.98+221617.9 0.048sp good
• ARG0002j29 SDSS J135817.73+171236.7 0.095sp not a disk galaxy?
• ARG0002j29 SDSS J135818.74+171300.6 0.095sp good
• ARG00022wh SDSS J112811.63+241746.9 0.16ph excellent
• ARG0002y6c SDSS J080217.94+112535.0 0.060sp good
• ARG0002ozz SDSS J144039.86+144122.6 0.080sp good not a disk galaxy
• ARG00028nb SDSS J142305.86+215735.5 0.13ph not a disk galaxy?
• ARG0001kwr SDSS J121659.93+323106.0 0.125sp good
• ARG0003o7j SDSS J022612.45+023307.4 0.145sp ?
• ARG0000x3e SDSS J092132.98+441345.2 4C 44.18 Seyfert_2 0.247sp poor (not a disk galaxy?)
• ARG0002oyw SDSS J104434.63+144204.0 (DR8 ID 1237661070863761563) 0.155sp not a disk galaxy?
• ARG000328n SDSS J124256.34+101305.9 0.17ph ?

EDIT TO ADD: I've added the redshifts* (and SDSS IDs, where missing) of the possible disk galaxy hosts, and a comment about my - purely subjective! - view on how good a candidate each is ("?" just means I haven't looked closely enough to say, yet).

UPDATE: I'm slowly doing detailed checking of each candidate, and posting images - mostly FIRST contours on Aladin SDSS9 images - in the GZ forum Friday, 21 February, 2014: Very Strange Spirals? thread (new ones on page 3). Sometimes I change my mind 😉

*sp = spectroscopic, ph=photometric

Posted

• I'm in the process of pulling together first a list of all possible discoveries reported here in RGZ Talk, in a post in the GZ forum thread Friday, 21 February, 2014: Very Strange Spirals?, direct link to that post.

Once the list is done, and its companion list of possible discoveries reported in the GZ forum, I intend to go through it, adding notes and composite images.

This list currently has ~30 objects 😮 Of course, not all will turn out to be disk galaxies associated with jet(s)/lobe(s), and some on the list are pretty marginal. On the other hand, this is just what I've pulled together so far ...

Now, about that paper ... 😃

Posted

• by JeanTate

On my first pass through some collections which overlap with my Collection 'Spirals' with a jet (or jets) and/or a lobe (or lobes), I found several that I'll investigate further (I've also added them to my Collection). Noting them here. But first, zutopian's Collection spirals has only 14 RGZ fields, but what a treasure trove it is! 😄

Two independent discoveries of already known disk galaxies with 'beyond the disk' radio emission: ARG0000b5m, and ARG00004w0.

EDIT TO ADD (12June): I've added the redshifts* and SDSS IDs of the possible disk galaxy hosts, and a comment about my - purely subjective! - view on how good a candidate each is ("?" just means I haven't looked closely enough to say, yet).

UPDATE: I'm slowly doing detailed checking of each candidate, and posting images - mostly FIRST contours on Aladin SDSS9 images - in the GZ forum Friday, 21 February, 2014: Very Strange Spirals? thread (new ones on page 3). Sometimes I change my mind 😉

*sp = spectroscopic, ph=photometric

Posted

In reply to @JeanTate's post regarding ARG00018d0, yes, I'd say that the disk galaxy in the foreground is a chance alignment.

Thanks heaps for compiling this valuable list of radio-loud disk galaxies!

Posted

• As of yesterday, Search returned 116 hits on 'spiral'. I've looked at all of these, and here are a handful that I think are worth following up on, not already noted (ones in bold I added to my Collection 'Spirals' with a jet (or jets) and/or a lobe (or lobes)):

• ARG0002kvu SDSS J113129.12+162336.3 0.172sp ?
• ARG0000fyb SDSS J130143.51+525327.2 0.033sp fair
• ARG0002xeg ? "nigh on impossible to tell anything!"
• ARG0000da3 SDSS J103556.67+542612.5 0.351sp fair (but I'm biased!)
• ARG00001rk - outside SDSS footprint
• ARG0002v6q NGC7479 0.00749sp no extended radio emission
• ARG0001dcd SDSS J144445.92+360622.0 0.352sp poor (“starburst”, but not disk morphology)
• ARG0000giy SDSS J090320.45+523336.1 0.351sp poor (ETG, with dusty spectrum)
• ARG00038ht SDSS J101740.90+080417.4 0.182sp poor (odd features, but not disk morphology)
• ARG0003q2w SDSS J083823.10+015012.4 0.559sp fair+ despite being very far away
• ARG0001cfs ?
• ARG0001182 SDSS J170256.86+421731.7 0.439ph fair+ despite being very far away

There are some others among the 116 which may be interesting - I didn't look very carefully - I'll check later.

Trivia: the summary Search gave, of the 116 (make of it what you will, given the heterogeneous nature of the 116 hits; my smilies):

• 83 objects
• 33 discussions
• 22 tag spiral 😄
• 10 triple
• 10 hourglass 😮
• 10 doublelobe 😃
• 7 overedge
• 6 compact
• 4 star
• 3 plume
• 3 disk 😃
• 2 wat

EDIT TO ADD (12June): I've added the redshifts* and SDSS IDs of the possible disk galaxy hosts, and a comment about my - purely subjective! - view on how good a candidate each is ("?" just means I haven't looked closely enough to say, yet).

*sp = spectroscopic, ph=photometric

Posted

• In reply to @JeanTate's post regarding ARG00018d0, yes, I'd say that the disk galaxy in the foreground is a chance alignment.

If we are quite confident about the FIRST astrometric accuracy, that conclusion seems sound. Thinking about this led me to wonder about what 'galaxy-galaxy overlaps' means, in radio astronomy ... some questions coming up, in a new thread! 😃

Thanks heaps for compiling this valuable list of radio-loud disk galaxies!

The pleasure is mine!

Small caveat: the only objects/fields I'm posting are ones where the host of the radio emission seems to be a disk galaxy, and where that radio emission extends (well) beyond the obvious optical boundaries of the apparent host. The morphology can be anything: doublelobe, hourglass, corejet, detached lobe (or pair of lobes), plume, x-shaped, ... I have certainly come across disk galaxies, as obvious hosts, which are also radio loud; however, the more distant ones are compact - Seyferts are good examples - and while there is extended - and loud! - radio emission for some closer disk galaxies, it is well within the optical (SDSS) limits.

I'm nearly done with the obvious searches I can think of, using RGZ Talk. I estimate I've found ~50 potential candidates, and of these I'd guess ~20 are good enough to at least warrant further investigation (i.e. beyond FIRST/NVSS/SDSS/WISE). Conservatively, zooites may have found perhaps ten robust 'spirals with hourglass/doublelobes', which is at least double the known examples (per what various astronomers have posted here, and in the GZ forum thread on this).

Not as newsworthy as Hanny's Voorwerp, perhaps, nor Green Peas; but worthy of some mention, wouldn't you say? 😄

Posted

• Having checked 'spirals', 'disky', 'disk', and 'disks', I've added the following four to my Collection 'Spirals' with a jet (or jets) and/or a lobe (or lobes):

• ARG0000g2d SDSS J093852.70+524943.9 0.047sp excellent
• ARG0002nur SDSS J081841.57+150833.5 0.33sp maybe
• ARG0001ulo SDSS J154240.76+275350.8 0.074sp not (radio emission is nuclear only)
• ARG00006do SDSS J142612.94+585401.6 0.27ph not disk morphology

While there are still a small number of other leads I've yet to follow, I'm now going to start to check all the potential candidates I've so far posted*.

If you - reader of this post - have come across any potential RGZ 'spirals' with jet(s) and/or lobe(s) that are not yet posted in this thread, please don't hesitate, post here! 😄

*to be clear: almost all of these were identified/discovered by zooites other than me; I'm simply collecting them

EDIT TO ADD (12June): I've added the redshifts^ and SDSS IDs of the possible disk galaxy hosts, and a comment about my - purely subjective! - view on how good a candidate each is.

^sp = spectroscopic, ph=photometric

Posted

• I'm nearly done with the obvious searches I can think of, using RGZ Talk. I estimate I've found ~50 potential candidates, and of these I'd guess ~20 are good enough to at least warrant further investigation (i.e. beyond FIRST/NVSS/SDSS/WISE). Conservatively, zooites may have found perhaps ten robust 'spirals with hourglass/doublelobes', ...

Current status: I have 82 objects in my file; I guess there are another ~dozen that might be added later. Five (so far) are duplicates, mistakes, etc; 21 I have yet to investigate. Of the remaining 56, 29 are basically out - not disk galaxies, impossible to tell, etc. Provisional - subjective! - rating of the rest:

• 5 excellent
• 8 good
• 7 fair
• 7 poor/marginal/maybe

And this is based solely on what zooites have reported, in comments or posts, here in RGZ Talk ... how complete is that selection?

Isn't astronomy fun?! 😄

Posted

• Great work collecting all this together!

I just came across another candidate here (the overedge bent triple due E not the central doublelobe):

The radio emission is weak in FIRST so I'm not sure if the core of the triple even generates a contour but the feature is bright in NVSS. I tried overlaying the SDSS r and NVSS to find the host and SDSS J100016.01+504518.8 Z_sp=0.134 looks to be best-placed, although I could be wrong. Although this galaxy has the appearance of a disk, the spectrum is closer to what I would expect of an elliptical, then again at that angle I would also expect a lot of dust. I would not expect a disk galaxy to be host to a bent source, either, as this appears to be.

Whether or not this one makes it onto the list I suspect higher resolution follow-up with both optical and radio is the way to go for your sample. If any of the hosts do not have spectra, those should probably be done as well. No one has ever had a statistically valid sample of disk/spiral galaxies with lobed radio emission to analyse before so they will need to be investigated thoroughly!

As to how complete the reported selection might be, consider that people will only have been able to make their comments for objects in the SDSS field of view. There are probably a few that are outside that have been missed but having a large enough sample allows for some estimates to be made for numbers in other parts of the sky. Looking at the angles of the disks might also suggest a bias, since distant spirals/disks seen nearly face-on might be harder to recognise as such.

Once again, great work!

Posted

• Thanks very much WizardHowl (do you mind if I call you WH?)! 😃

After I posted the 'current status' summary, I thought some more about completeness ...

And this is based solely on what zooites have reported, in comments or posts, here in RGZ Talk ... how complete is that selection?

And that led me to take a hard look at 3C 285 (I just posted the results in the GZ forum thread, link to post). So far, not counting 3C 285, we ordinary zooites seem to have found two 'already known' sources, independently (NGC 3079/ARG0000b5m, and ARG00004w0). The GZ forum thread has at least two (others?), which means that we have found them all! 😮 Here's raynorris, from the OP of this thread:

These objects are incredibly rare in the local Universe (only 2 or 3 known)

So here's an idea for checking completeness: of a (complete!) list of known objects, how many are in the RGZ footprint? within that, how many are in the SDSS footprint? of those, how many have been served up to zooites to classify so far? Etc.

At this point, definitions and criteria become crucial.

For example, how do we count lenticulars (early-type galaxies with disks)? galaxies with 'disturbed morphologies' (e.g. mergers)? what criteria do we use - other than subjective opinions - to eliminate 'chance overlaps/alignments'? On the radio side, must there be unambiguous evidence of two lobes/jets (or will just one - extending beyond the optical boundary - do)?

Having gotten me all fired up, by his "hey, I'm back!" post (May 26 2014 1:43 PM), I'm a little puzzled as to why raynorris hasn't so much as said 'cool!' since ... is this what scientists usually do?

Posted

• by JeanTate

Test, test, test, test, ...

ARG0002whf: FIRST contours overlay, linear, smoothing 4, 5 levels, min=0 (on top of SDSS r-band image). About the same size as the ARG image ...

Test, test, test, test, ...

Posted

• Thanks again, WH. I'll add '0jzh' to my file (so far, every ARG ID is unique in only the last four characters).

Although this galaxy has the appearance of a disk, the spectrum is closer to what I would expect of an elliptical, then again at that angle I would also expect a lot of dust. I would not expect a disk galaxy to be host to a bent source, either, as this appears to be.

As you'll see from my next post, I've got a first-pass set of criteria for selecting, and grading, candidates; "lots of dust" is high on the list! 😃

... I suspect higher resolution follow-up with both optical and radio is the way to go for your sample. If any of the hosts do not have spectra, those should probably be done as well. No one has ever had a statistically valid sample of disk/spiral galaxies with lobed radio emission to analyse before so they will need to be investigated thoroughly!

Astronomy in a nutshell! 😄 Since change is far too slow, collect huge numbers of objects, and then analyze them for patterns (having first adequately addressed selection effects/biases). Now if only we could teach a machine to find every galaxy with extended (beyond optical boundary) radio emission, except boring ellipticals ... 😉

As to how complete the reported selection might be, consider that people will only have been able to make their comments for objects in the SDSS field of view. There are probably a few that are outside that have been missed but having a large enough sample allows for some estimates to be made for numbers in other parts of the sky.

That's my hope. However, you and I are at a severe disadvantage ... we have no information whatsoever on the distributions of ARG fields - not even any info on how they were selected - much less on patterns of reporting/commenting. I wonder if any RGZ SCIENTIST would be willing to let at least you or I in on this?

Looking at the angles of the disks might also suggest a bias, since distant spirals/disks seen nearly face-on might be harder to recognise as such.

Well, if we do end up with ~100 candidates, we may have enough data to take a stab at estimating this ... 😮 How's your statistics?

Posted

• At this point, definitions and criteria become crucial.

For example, how do we count lenticulars (early-type galaxies with disks)? galaxies with 'disturbed morphologies' (e.g. mergers)? what criteria do we use - other than subjective opinions - to eliminate 'chance overlaps/alignments'? On the radio side, must there be unambiguous evidence of two lobes/jets (or will just one - extending beyond the optical boundary - do)?

I've just written a post, over in the GZ forum, on this (direct link).

In a nutshell, I think we should aim to find "any galaxy - other than a boring elliptical - which seems to have radio emission outside the optical boundary, or extending beyond that boundary"

How to decide if a likely host galaxy is 'a boring elliptical' or not? The usual zooite method (but blue ellipticals as hosts are definitely to be noted! they likely contain gas and dust), plus astronomers' tests (e.g. concentration ratio, color, Sérsic profile index).

So, a simple two-part test; how likely is it that:

1. this galaxy is the host?
2. this host galaxy is not a boring elliptical?

Posted

• Some more ARG fields with SDSS objects of possible interest, which have not yet been posted in this thread. The following are all "poor" candidates, I feel (but I'd be delighted if you were to disagree, and present a strong case! 😄):

And the following six are on my "yet to check out" list:

Posted

• Provisional - subjective! - rating of the rest:

• 5 excellent
• 8 good
• 7 fair

(I don't really care about any other category). A day later, here's how things stand:

• 9 excellent
• 8 good
• 8 fair

Still some work to do, on trying to ensure consistency, and checking ~ a dozen candidates. Also, I need to start looking at new objects ...

Here's an idea for a Zooniverse project, a spin-off of RGZ:

• pick a redshift range, in which most likely doublelobes/hourglasses/etc will not be overedge
• select all 'debiased SDSS spirals' in this range, using GZ1 and GZ2
• select those which are fully within FIRST
• present to zooites, to classify! 😃

From the zooites' point of view, the major differences would be that a) there may not be a radio source in the center of each field (it'd be staggering if there were!), and b) some fields would have no radio sources at all. Likely would have to add a carefully selected sample of 'non-spirals' (elliptical, merger, don't know, star/artifact), as a control.

Thoughts?

Posted

• Other astronomers than the authors of the new paper (see my previous post: click above) also found recently a spiral with jets, but it's currently just a candidate.:

Title: Large Radio Sources Hosted by Spiral Galaxies (aka: The Wrong Type of Host!)
Authors: Duffin, Ryan; Mao, M.; Owen, F. N.
Publication: American Astronomical Society, AAS Meeting 223, 250.21
Publication Date: 01/2014
Origin: AAS
Abstract Copyright:(c) 2014: American Astronomical Society
Bibliographic Code: 2014AAS...22325021D

They started a project to search for spirals with jets and they found as 1st candidate SDSS J164924.01+263502.6 .:
http://skyserver.sdss3.org/dr9/en/tools/explore/obj.asp?id=1237662301913940522

Is a Radio Zoo image of this galaxy available ?

Posted

• Don't know about an RGZ image (and can't check if any has been posted here in Talk or not, because there's no ability to search by position), but I did create a composite image (DR10 SDSS plus FIRST contours), which I posted in the GZ forum thread (here).

Copy:

Posted

• by zutopian

@JeanTate

Thanks for checking all the candidates ! Great work !
I found a further candidate today.: http://radiotalk.galaxyzoo.org/#/subjects/ARG00032pb
I added it to my collection "Spirals". Could you please check ?

Posted

EDIT: Here is a further one.:

Posted

• by JeanTate

Not an RGZ object (that I know of anyway), but quite relevant (I hope!).

The galaxy SDSS J023832.67+023349.1 is in the center of this DR10 cutout, 432"x432" (600x600 pix @0.72"/pix):

And a DR10 (straight), FIRST (red, mild Gaussian blur, threshold), and NVSS (cyan, substantial Gaussian blur, threshold) composite:

A close-up of the galaxy which is, apparently, the cause of all this radio emission (it's the bright red spot, in the center 😉 ):

Whatever it is, it isn't a boring elliptical, even if you (somehow) ignore the bright AGN. And is the radio emission - clearly centered on this galaxy - a #wat? or a #doublelobe?

Copied from my GZ forum post here; Tony Wei seems to have noticed this first. This is one - of seven (currently) - candidate objects ("Hourglass sources associated with spiral galaxies") posted in the GZ forum by zooites, apparently independently (and quite unrelated to any reported here in RGZ Talk). My list - which I'll keep updating by editing the post - is here.

Posted

I love these "boring" sleeper galaxies that are in fact stirring up the IGM like crazy!

Posted

• As I've posted these in the GZ forum thread (here), for completeness, I'll post them here too. They are all 'else':

There's also:

Posted

I started a discussion topic, namely "Paper: Spiral with jets discovery by Bagchi et al.".:

Posted

• These objects are incredibly rare in the local Universe (only 2 or 3 known) ...

I've been trying to track down these "2 or 3"; here's what I have found:

• 0313-192 (Ledlow+ 1997, and Keel+ 2006)
• NGC 5548 (Liu+ 2002? likely earlier, but I can't find any)
• SDSS J084002.36+294902.6/FIRST J084000.8+294838 (Liu+ 2002? likely earlier, but I can't find any)
• SDSS J140948.85-030232.5 (Hota+ 2011; Speca, "[it] could possibly be the second spiral-host large radio galaxy", presumably after 0313-192)
• 3C 285 (I don't know)
• ARG00004w0, per HAndernach
• J2345-0449 (Bagchi+ 2014, after the OP was written)
• SDSS J164924.01+263502.6 (Duffin+ 2014*, ditto)

I'm not sure if NGC 3079 (ARG0000b5m) should be included or not. By my criterion of "radio emission extends beyond the optical boundary" it would not ...

Rather more than two or three ... 😦

*"During the course of this research, a second spiral galaxy that appears to be hosting a double-lobed radio source was identified" Hmm, that's at least the second second 😄

Posted

• by JeanTate

I'm going to take a bit of a break from creating composite images and trying to classify the candidates I've found in RGZ Talk so far*, so I can spend some time learning how to use Python to do analyses of the candidates (see this post for some background etc). I'll still be looking at new comments, and collecting possible candidates.

Here are some 'as of now' stats, which may be of interest:

• 97 records in my file, one record per potential candidate (but see below!)
• 9 are duplicates, independent discoveries, errors, etc
• excluding the 9, 78 records were collected before I first posted my intentions in this thread, and ten since

Of the 78:

• 8 are "excellent" (one has yet to be posted in the GZ forum thread)
• 7 are "good"
• 10 are "fair" (two have yet to be posted in the GZ forum thread)
• 23 "poor"
• 21 "else"
• 9 "yet to be rated"

Most of these 9 "yet to be rated" are complicated, for one reason or another; most are likely to end up being either "poor" or "else".

More intensive searching could turn up another ~20 candidates, among comments posted before ~10 June. Very roughly, then, ~15 candidates per month.

Of the ten candidates I've noted since 10 June, I've rated just one (and posted it to the GZ forum thread), ARG00026v8. If the distribution is ~the same as among the 78, another 2 or 3 of these ten will be excellent/good/fair. The 'rate of discovery' is about the same, perhaps a tad higher.

How many excellent/good/fair might there be, among those no one has commented on yet? I cannot answer that, but maybe a scientist could ... How to factor in the 'zooite'? Here's the number of candidates by zooite, ignoring their 'hit rate' among candidates (and counting independent discoveries - two or more zooites independently find the same candidate - just once):

• 24 WizardHowl
• 20 antikodon
• 16 zutopian
• 7 JeanTate (surely biased! 😮)
• 3 firejuggler
• 2 each: c_cld, Dolorous Edd, inforservador
• 1 each: bartinhogoool, Brucea, Emmabray, jesse.rehm, mdwilber, Milkybear, planetaryscience, SG1966, sharqua, teamaynard, Ushiromiya Xyrius

Oh, and we need just a fifth (or even less?) of the 25 excellent/good/fair objects to turn out to be the real thing, in order to double the current known number of these systems. 😮 How cool is that?!? 😄

*to be very clear: almost all these were discovered by zooites other than JeanTate

Posted

• by 42jkb scientist, admin in response to JeanTate's comment.

This is great work! An excellent collection.

Ray will be back on line in July and should get back to this science project shortly thereafter.

Posted

• Here is a further paper.:

(...) Unlike most FR-II objects, W2332-5056 is hosted by a disk-like galaxy. (...)

Chao-Wei Tsai, Thomas H. Jarrett, Daniel Stern, Emonts Bjorn, R. Scott Barrows, Roberto J. Assef, Ray P. Norris, Peter R. M. Eisenhardt, Carol J. Lonsdale, Andrew W. Blain, Dominic J. Benford, Jingwen Wu, Brian Stalder, Christopher W. Stubbs, F. William High, K. L. Li, Albert K. H.Kong
(Submitted on 8 Oct 2013)
http://arxiv.org/abs/1310.2257

In this paper there are mentioned further cases, e.g. following ones.:

• disk-like galaxy PKS 1814-636 (Morganti et al. 2011)
• NGC 612 (Ekers et al. 1978). This one is also mentioned in the paper by Keel et al. .
• and further ones

Posted

• I have attempted to find a few more examples by going back through the objects I have commented on that did not appear to be obviously QSO or red+dead galaxies. I collected these together ( http://radiotalk.galaxyzoo.org/#/collections/CRGS0000o6 ) (80 objects currently, I'll add more as I encounter them) erring slightly on the generous side as to what to include and then divided them up into one or more categories based upon why I had included them: non-red colour; extended shape; disturbed/irregular shape (including signs of interacting) and also a category for very faint objects about which it was difficult to say much (although usually these would also be in the non-red colour group). These are the four collections and the current number of objects in each:

There is the usual caveat that I might not have correctly identified the host or it might be a background source with a strange galaxy on a line-of-sight. In a couple of cases the galaxy I'm referring to is not related to the central radio emission but another radio source elsewhere in the image, although in these cases my comments point this out.

In terms of looking for spirals/disks, most are likely to be found in the extended category but there are a couple of face-on examples previously mentioned in this thread that are not in that collection and instead in the non-red colour group. The only new face-on spiral candidate that is only in the non-red group is http://radiotalk.galaxyzoo.org/#/subjects/ARG0000oc1 (SDSS J104151.75+483149.1 Z_ph~.3-.4 Doublelobe). As I was erring on the generous side the extended collection may also include red+dead lenticular galaxies but the reason I have not highlighted these before is largely because I was not certain enough to call them out as disk candidates. Most of the new objects are fainter and smaller than those already appearing in this thread but 13 of these are also non-red-coloured and might be blue ellipticals or some other type instead of disks. The 22 objects in the extended group not already mentioned in this thread are:

http://radiotalk.galaxyzoo.org/#/subjects/ARG0002phe (I suspected lensed QSO, not disk)

http://radiotalk.galaxyzoo.org/#/subjects/ARG0001gr4 Also non-red, slightly disturbed. Corejet

http://radiotalk.galaxyzoo.org/#/subjects/ARG0000ik1 Also non-red, very faint. Hourglass

http://radiotalk.galaxyzoo.org/#/subjects/ARG000150p Also non-red, very faint. Corejet

http://radiotalk.galaxyzoo.org/#/subjects/ARG0002ool Also non-red, very faint. Triple

Posted

• by zutopian

Listed by WizardHowl in previous post:

(...)
(...)

It is NGC 5972., which has a known voorwerpje (ionized gas cloud). Ref.: GZ paper by Keel et al..
One of the other NED Refs is as follows.:.

Title: The Hubble type of the double lobe radio galaxy NGC 5972.

We found in the literature a single example of a spiral galaxy associated with a classical extended double lobe radio source: NGC 5972 classified as an S0-a by Lauberts (1982). We show that it is rather an E galaxy which may possibly be the result of a merger event. It has an emission line spectrum typical of a Seyfert 2 galaxy.

Authors: Veron, P.; Veron-Cetty, M.-P.
Publication: Astronomy and Astrophysics, v.296, p.315 (A&A Homepage)
Publication Date: 04/1995
Origin: CDS; KNUDSEN
Bibliographic Code: 1995A&A...296..315V

The paper was cited in following paper.:
Title: An Unusual Radio Galaxy in Abell 428: A Large, Powerful FR I Source in a Disk-dominated Host
Authors: Ledlow, Michael J.; Owen, Frazer N.; Keel, William C.
Bibliographic Code: 1998ApJ...495..227L

Here is the GZ blog post about the observation by the HST.:
Something rich and strange – Hubble eyes NGC 5972

(...)This is a galaxy with active nucleus, large double radio source, and the most extensive ionized gas we turned up in the Voorwerpje project. (...)

http://blog.galaxyzoo.org/2012/07/12/something-rich-and-strange-hubble-eyes-ngc-5972/

I started following discussion.:

NGC 5972.: Galaxy with known voorwerpje and known doublelobe

EDIT: I did further posts related to the morphology in that discussion.

Posted

• by JeanTate

There's a paper just out which may help us a lot: A Catalogue of Two-Dimensional Photometric Decompositions in the SDSS-DR7 Spectroscopic Main Galaxy Sample: Preferred Models and Systematics, Meert+ 2014:

We present a catalogue of two-dimensional, PSF-corrected de Vacouleurs, Sersic, de Vacouleurs+Exponential, and Sersic+Exponential fits of ~7×105 spectroscopically selected galaxies drawn from the SDSS DR7. Fits are performed for the SDSS r band utilizing the fitting routine GALFIT and analysis pipeline PyMorph. We compare these fits to prior catalogues. Fits are analysed using a physically motivated flagging system. The flags suggest that more than 90 percent of two-component fits can be used for analysis. We show that the fits follow the expected behaviour for early and late galaxy types. The catalogues provide a robust set of structural and photometric parameters for future galaxy studies. We show that some biases remain in the measurements, eg. the presence of bars significantly affect the bulge measurements although the bulge ellipticity may be used to separate barred and non-barred galaxies, and about fifteen percent of bulges of two-component fits are also affected by resolution. The catalogues are available in electronic format. We also provide an interface for generating postage stamps images of the 2D model and residual as well as the 1D profile. These images can be generated for a user-uploaded list of galaxies on demand.

By getting the results of these 2D model fits, for candidate hosts in SDSS DR7, we would (will) have a more objective basis for classifying the host's optical morphology, and hopefully enough data to formulate hypotheses concerning late-type vs early-type, signs of merger/interaction, and may even be able to extrapolate to better classifications of more distant/fainter candidate hosts.

And when raynorris returns, he can tells us how any of this relates to PRONGS! 😃

Posted

• This is really awesome, WizardHowl! 😃

One thing to look into: how many of these were independently commented on, by other zooites? That could give a handle on estimating how many of these 'rare' objects there are, in the ~170k RGZ fields, by putting bounds on completeness (something like this: WizardHowl and antikodon will comment on every candidate, if they get it to classify; how many RGZ fields have they classified? of those fields, how many contain candidates? of the commented fields, how many also have comments by other zooites? etc).

Posted

• by zutopian

CHANG-ES III: UGC10288 -- An Edge-on Galaxy with a Background Double-lobed Radio Source
Judith Irwin, Marita Krause, Jayanne English, Rainer Beck, Eric Murphy, Theresa Wiegert, George Heald, Rene Walterbos, Richard J. Rand, Troy Porter

A surprising new result is the presence of a strong, polarized, double-lobed extragalactic radio source ({\it CHANG-ES A}) almost immediately behind the galaxy and perpendicular to its disk.

(Submitted on 14 Nov 2013)
http://arxiv.org/abs/1311.3894

Posted

• by zutopian

I started a discussion.: NGC 5775: Spiral galaxy with a known giant jet ?

Posted

• by zutopian

I found another candidate.:

Discussion: ARG0000hpu associated with Spiral ? :

Posted

• by zutopian

A further candidate:

Discussion: ARG0000tg3 : A disk galaxy ?

It looks like a big and round elliptical, but one of the NED Refs is the paper "2010MNRAS.406.1595F Scalelength of disc galaxies".

Posted

• by zutopian

Discussion: ARG0002dun associated with edge-on?

Posted

• I just posted this, in the How to decide the 'zero point' for radio contours? thread (page 2):

FIRST contours are in red, smoothed NVSS ones in cyan. I don't know about you, but it seems to me that the host of the nice doublelobes is likely to be some 'invisible' (in the SDSS image) far background galaxy, rather than the z_sp = 0.044 spiral. 😦

Posted

• by JeanTate

Newbie zooite civilsparky found one, ARG0003a73. See the Great Example? thread for details.

Posted

• by zutopian

Posted

Posted

• by JeanTate

Blue edge-on disk-like host SDSS J152037.74+272855.4 in ARG0001vko:

Posted

• Triple with disk-like but also disturbed-looking host with weird spectrum http://radiotalk.galaxyzoo.org/#/subjects/ARG0000hga

Spectrum has odd continuum with lots of absorption and also narrow-line emission, classed as AGN from the SDSS interactive spectrum tool. SDSS J123847.46+520302.1 Z_sp=0.221

Posted

• by JeanTate

As some of you may have noticed, Hanny has just announced the closing of the Galaxy Zoo forum, after seven years (This will be the last Object of the Day on our forum…!).

This means that the thread there (Friday, 21 February, 2014: Very Strange Spirals?), in which I was collecting and collating all the candidates mentioned here, is now a fossil*. In the next week or so I will try to copy as much of the core content as I can, in that thread, over here. And this RGZ Talk thread will likely become the primary repository.

Does anyone know how to do a bulk copy/paste of a thread in an SMF forum?

*One thing Hanny didn't make clear is that all threads and posts in the GZ forum are now locked; no new threads, no quoting, not even any modifying of your own posts.

Posted

• by JeanTate

ARG0001t4p - likely host a z_sp 0.316 edge-on disk galaxy; spectrum is red, but more likely due to dust than 'dead'

Posted

• by JeanTate

ARG0000uce - unusual doublelobe with Eos host

Posted

• by zutopian

The Hunt Is On

We are pleased to announce that the Radio Galaxy Zoo community has identified over a dozen potential candidates and we are in the process of following these up.

http://blog.galaxyzoo.org/2014/07/31/the-hunt-is-on/

Posted

• http://radiotalk.galaxyzoo.org/#/subjects/ARG0000whi -- very slightly bent overedge doublelobe, only candidate for host is disk galaxy SDSS J102505.47+443015.4 Z_ph~0.11-0.12

Posted

Two of our scientists (Ray Norris and Minnie Mao) have begun to sift through the sources you have identified and will keep you informed of their progress. Thanks for identifying these for us!

Posted

• Very cool! 😄

I just started a thread, What are our VERY BEST 'hourglass sources associated with spirals'?, to collect what we ordinary zooites think are our individual Top Ten candidates ("Ten" may be a somewhat, um, elastic number).

Posted

• Following akapinska's comment ("I would rather take the galaxy detected clearly in both optical (SDSS) and infrared (WISE). Also, with FIRST resolution we don't really know where exactly the radio core is, hence my best bet would be the SDSS galaxy J104516.56+090301.1"), SDSS J104516.56+090301.1 may be the disk galaxy host for ARG00035pg.

Posted

• Catch up/status post.

I'll still be looking at new comments, and collecting possible candidates. [...] Here are some 'as of now' stats, which may be of interest: [...] 97 records in my file, one record per potential candidate (but see below!); 9 are duplicates; independent discoveries, errors, etc; excluding the 9, 78 records were collected before I first posted my intentions in this thread, and ten since

Of the 78: 8 are "excellent" [...]; 7 are "good" [...]

More intensive searching could turn up another ~20 candidates, among comments posted before ~10 June. Very roughly, then, ~15 candidates per month.

Of the ten candidates I've noted since 10 June, I've rated just one (and posted it to the GZ forum thread), ARG00026v8. If the distribution is ~the same as among the 78, another 2 or 3 of these ten will be excellent/good/fair. The 'rate of discovery' is about the same, perhaps a tad higher.

That was written on 18 June. So my 'catch up' is:

• rate the other 9 candidates I noted, between 10 and 18 June
• look for candidates posted - either here in this thread or in object comments - and rate them
• intensely search object comments posted before 10 June (however, I do not intend to do this).

Right now, though, I'm going to make sure all 15 'excellent' or 'good' candidates are checked out as best I can: overlay image, inverse concentration index, ellipticity, GZ1 and GZ2 morphology votes, ... I'll be posting my 'Top Ten' in the What are our VERY BEST 'hourglass sources associated with spirals'? thread.

Posted

• It's ARG0001xiw; here's a FIRST contours overlay image:

I think it's fair to day that if WizardHowl, zutopian, Dolorous Edd, antikodon, 1001G, ... Jean Tate ... had got this to classify, we'd have immediately commented on it! 😃

On going through the candidates - mentioned in this thread and in the GZF one - I've been struck by how many are similar to this, in that the (candidate) host is 'red' (i.e. no obvious star-forming regions in the arms), dusty (dust lane(s), reddened spectrum), and shows signs of a recent interaction/merger. Close to none are like 0313-192. 😮

Here's the galaxy itself, and its SDSS spectrum (pretty 'dead and red'):

Boilerplate: SDSS image per http://skyservice.pha.jhu.edu/DR10/ImgCutout/getjpeg.aspx, FIRST (red) contours derived from the FITS file produced using SkyView with Python code described in this RGZ Talk thread. Image center is the galaxy SDSS J164924.01+263502.5, near the ARG image (ARG0001xiw; J2000.0). "z_sp" is an SDSS spectroscopic redshift of the galaxy in the center.

Posted

• I think it's worth doing FIRST and/or NVSS contour overlays on SDSS images of these '2 or 3' (where possible), to see how they compare with the best candidates we've been finding.

Of the eight in the list (copied below), one is definitely outside the SDSS footprint, and two already have such contour overlay images. It may be that features which make these certain associations include obvious radio emission from the galaxy nucleus, and low redshift (<~0.15, say).

In the post after this, I'll display SDSS images at 0.2"/pix and contour overlay images, in the same way I've done in the FIRST contours overlaid on SDSS images - our VERY BEST 'doublelobe spirals' thread.

Here's the list, without the links and footnote, plus a note:

• TOO FAR SOUTH 0313-192 (Ledlow+ 1997, and Keel+ 2006)
• IMAGE+ HERE NGC 5548 (Liu+ 2002? likely earlier, but I can't find any)
• SDSS J084002.36+294902.6/FIRST J084000.8+294838 (Liu+ 2002? likely earlier, but I can't find any)
• SDSS J140948.85-030232.5 (Hota+ 2011; Speca, "[it] could possibly be the second spiral-host large radio galaxy", presumably after 0313-192)
• 3C 285 (I don't know)
• ARG00004w0, per HAndernach
• J2345-0449 (Bagchi+ 2014, after the OP was written)
• IMAGE UP-PAGE SDSS J164924.01+263502.6 (Duffin+ 2014, ditto)

Posted

• NGC5548; contour overlay centered on ARG00020sx

SDSS J084002.36+294902.6/FIRST J084000.8+294838 ARG0001qln

SDSS J140948.85-030232.5 "Speca"

3C 285 ARG00010ly

"Bagchi" J2345-0449

SDSS J164924.01+263502.6 ARG0001xiw

Boilerplate: SDSS image per http://skyservice.pha.jhu.edu/DR10/ImgCutout/getjpeg.aspx, FIRST (red) and NVSS (cyan) contours derived from FITS files produced using SkyView with Python code described in this RGZ Talk thread.

Posted

• Capturing some thoughts:

• the ~eight already reported in the literature have redshifts < ~x; assume no evolution and a flat universe (out to ~0.4), how many candidates would you expect us zooites to find, between x and 0.4?
• what does the redshift distribution of the excellent/good/(fair?) candidates look like?
• if Duffin+ 2014 apparently missed so many reported objects (already in the literature), how many more have been missed, by us zooites?
• it seems low z QSOs and Seyferts (< ~0.3) may not have been systematically checked, re nature of host and FIRST/NVSS sources (esp giants?); worth our while to do so (there are plenty of catalogs)?
• ditto voorwerpje candidates (the GZF has at least one list, and maybe BillK would be interested?), and EELR/green beans/green peas; at least one such object is a radio source, as noted upthread (but not a disk galaxy)
• if not-boring-ellipticals with doublelobes seem to include lots of late/post-mergers (Cen A anyone?), maybe post-quenched galaxies - many of which are clearly spirals - will also host doublelobes?

Posted

• Adding a couple of recently-encountered candidates, the first looks more convincing but the other two are distant enough that higher resolution optical images would be needed to confirm a disk nature (though both have spectra I don't know how to distinguish between an ETG and an edge-on disk, although one has a flatter continuum that does not look like an ETG):

http://radiotalk.galaxyzoo.org/#/subjects/ARG0001pvc -- overedge doublelobe, seems half-way between ETG and disk SDSS J142558.12+300931.2 Z_ph~0.26-0.29

http://radiotalk.galaxyzoo.org/#/subjects/ARG0000wgq -- extended emission, faint but spiral-like? non-red colour, spectrum continuum not ETG-like SDSS J123826.01+443137.1 Z_sp=0.312

http://radiotalk.galaxyzoo.org/#/subjects/ARG00015jc -- doublelobe, host has extended shape but ETG colours SDSS J100457.45+400556.0 Z_sp=0.453

Posted

• if not-boring-ellipticals with doublelobes seem to include lots of late/post-mergers (Cen A anyone?), maybe post-quenched galaxies - many of which are clearly spirals - will also host doublelobes?

How prescient? 😮 Check out ARG0000hga - the "missing link" disk galaxy! Magic word: "quenched". For the record, WizardHowl had this as his #11 "Top Ten". Let the "how many E+A galaxies are associated with doublelobes?" project begin! 😃

Ray, Ivy, Julie, are you in?

Posted

• by JeanTate

Just posted J0238+0233 - a "doublelobed spiral" found by zooite Tony Wei. So far I've not been able to find an ARG ID associated with any FIRST source ... 😦

UPDATE: WizardHowl identified one of the source in the NE lobe as ARG0003o4w.

Posted

• Status, not including the three most recent candidates posted by WizardHowl:

• all 8 'excellent' candidates are among the (combined) 17 Top Ten of WizardHowl and myself
• the remaining 9 are all 'good'
• there are 7 other 'good' candidates, not in the combined Top Ten (see below)
• and 21 'fair' ones (see below)
• not counting the 3 most recent posted by WizardHowl, I have 8 'not yet rated' (one is outside the SDSS footprint); however, I expect none will fare better than fair

Here are the 7 other 'good' candidates, in no particular order:

And my list of 'fair' candidates, also in no particular order:

Posted

@JeanTate: Just a note that E+A galaxies will tend to be composed of non-spirals since their spectra will look like a typical early-type galaxy. Since post-starbursts are one of my "pet-type" of galaxies, I'd love to join you all for your searches. Perhaps we need a separate link for such a project?

Posted

• Thanks Ivy.

Perhaps we need a separate link for such a project?

I agree.

Posted

• This source looks more like a corejet rather than a lobe but it seems to extend beyond the host galaxy, which is an edge-on disk SDSS J135152.97+465026.2 Z_sp=0.096.

Posted

• by JeanTate

Host of ARG0003nwu may be a z_ph 0.12 Eos SDSS J015744.20+024044.9

Posted

• Host of nice #doublelobe ARG0001c36 may be not-boring-elliptical z_ph 0.23 SDSS J084640.78+364159.5:

Posted

Hi all,

Just thought that I'd mention the following paper which showed that sometimes the spiral host may be a foreground object and that the true host may be a background object at higher redshifts. .....

Posted

• by mini.mintaka scientist

Wow! There are so many really cool candidates found!

I think people have mentioned this above, but something I'd like to know is the relationship between these hourglass sources hosted by spirals, and Seyfert galaxies. Seyfert Galaxies can have extended radio emission, but typically only on a parsec-scale... maybe the most extended radio emission associated with Seyferts is a few kpc? I wonder if any of the spiral hosts show Seyfert spectra?

this stuff is fascinating! thank you guys!

Posted

• Thanks Ivy.

That was published in 1983, and is about radio source PKS 0400-181 and a z_sp 0.0367 spiral galaxy; ADS lists six subsequent papers (etc) which cite it. Of these:

• Roennback&Shaver 1997 (RS97) confirm that the background object is the host of PKS 0400-181, a z_sp 0.341 elliptical
• Ledlow+ 1998 (L98) reports the discovery of 0313-192, an Eos associated with doublelobes
• Véron-Cetty&Véron 2001 (V01) report the discovery of the association between NGC 612, an S0 (lenticular) and the FR II radio source PKS 0131-36

Looking at the papers which cite the six (there are rather a lot!), here are some which seem to be of direct interest for this thread (I make no claims about completeness or what 'of interest' means!):

• (L98) Lamer+ 1999 report observations showing the BL Lac object PKS 1413+135 is indeed the nucleus of the (local) disk galaxy
• (L98) Ledlow+ 2001 detailed analysis of 0313-192
• (L98 and V01) Keel+ 2006 HST observations of 0313-192
• (L98 and V01) Emonts+ 2009 "We present new observational results that conclude that the nearby radio galaxy B2 0722+30 is one of the very few known disc galaxies in the low-redshift Universe that host a classical double-lobed radio source"
• (L98) Hota+ 2011 "We report the discovery of a unique radio galaxy at z= 0.137, which could possibly be the second spiral-host large radio galaxy and also the second triple-double episodic radio galaxy."
• (L98 and V01) Morganti+ 2011 not doublelobes, but "We present a detailed study of PKS 1814-637, a rare case of powerful radio source [...] hosted by a disk galaxy."
• (L98) Bagchi+ 2014 "Megaparsec Relativistic Jets Launched from an Accreting Supermassive Black Hole in an Extreme Spiral Galaxy"

A few more overlays might be interesting, even if they are FIRST (and NVSS?) on RGB DSS2 images (of my own creation) rather than on SDSS images: PKS 0400-181, 0313-192, NGC 612/PKS 0131-36, PKS 1413+135, B2 0722+30, and PKS 1814-637 (images of the galaxies reported in Hota+ 2011 and Bagchi+ 2014 are already posted in this thread, on page 9).

Posted

• Thanks! 😄

Considering only SDSS spectra, here are the numbers, by my rating*:

• excellent: 5, of 8
• good: 8, of 18
• fair: 14, of 27

How many of the 27 have "Seyfert spectra"? Hmm ... if the fiber aperture does not include the nucleus, the spectrum won't/can't be of the Seyfert kind.

But if it does, how to tell if the spectrum is Seyfert-like?

Well, if there are strong emission lines, and if the permitted lines (such as Hα and Hβ) are broad/have an obvious broadline component, that's one way. But if the strong emission lines are all narrow? Only a BPT diagram could tell an AGN-dominated nuclear spectrum from a composite or starburst/intense star-forming one, right?

*the totals are different from those in my post of August 7 2014; I've added 2 'good', and 6 'fair' since then (but no new 'excellent's, sadly)

Posted

• Looking at the 27 SDSS spectra, starting with the five 'excellent' candidates:

• ARG00012kb/SDSS J091445.53+413714.3: "AGN Broadline", so YES
• ARG0002g0s/SDSS J130140.93+183104.9: narrow-line, star-forming? try BPT
• ARG0000hga/SDSS J123847.46+520302.1: "AGN", narrow-line (and post-quenched)
• ARG00023wq/SDSS J120301.43+235319.9: "QSO Broadline", so YES
• ARG0003o7j/SDSS J022612.45+023307.4: narrow-line, star-forming? try BPT

Three definite, two require further analysis.

The eight good:

• {later}

Posted

• At 18 June, 2014, I estimated the rate of discovery of 'doublelobes associated with spirals' candidates to be ~15 per month.

I have just finished going through all the 'Recent Object Comments', from 23 July to yesterday, noting candidates. Since 18 June, I have added 69 candidates to my database 😮

Of these 69, 18 have 'discovery dates' before 18 June. The coincidence with "More intensive searching could turn up another ~20 candidates, among comments posted before ~10 June" (which I wrote on ~10 June) is remarkable, don't you think?

Of these 18, one I rated 'excellent'*, one 'good', and three 'fair'; there are three I have yet to rate.

Of the 51 'discovered' since 18 June, three are excellent, six good, and seven fair; 26 I have yet to rate (nearly all are candidates I added just a short while ago).

On its face, the discovery rate would seem to have picked up greatly, especially considering that I have not yet checked 'Recent Object Comments' from 18 June to 22 July; however, a more useful metric would be the discovery rate of excellent/good/fair candidates ... stay tuned ... 😉

*caveat: between 10 June and now, I began to use overlay images as part of the rating process; some objects now have different ratings from what they had back then

Posted

69 candidates!?! Great work everyone.

Posted

• by zutopian

A further candidate:

Posted

• by mini.mintaka scientist

JeanTate, did you say there are 69?!!?! phwoar! that is so awesome! Thanks so much everyone!

Good thinking about the aperture of the fibre. I think SDSS fibres are 2arcsec... many of the sources that are unequivocally classified as spiral galaxies will be at low redshift... so the galaxies may span a much larger size than the fibre! As you correctly point out, for Seyferts, the distinctive emission lines should emanate from the bulge. However, for "normal" spiral galaxies, the spectrum may actually look like that of a "normal" elliptical because the fibre sees only the bulge...

Posted

• Before SDSS, the best 'covers lots of the sky, consistently' imaging survey was DSS2. And outside the SDSS footprint, it's still the best (as far as I know).

SkyView does not have a "Parkes survey" option, for obtaining FITS images; however, it does have a VLSSr one. Using these sources, and with some fiddling, I produced this overlay:

The background elliptical does not seem to be detected in the DSS2 data, and the VLSSr resolution is pretty low (compared with that of FIRST); nonetheless, it does rather appear that the spiral galaxy is the host of extended radio emission (spiral? well, it's blue - elliptical galaxies with this redshift would not be blue - and rather too 'out of round' to be an elliptical; also, it does seem to have some structure, even if actual arms are not resolved).

Here's an interesting question: if we had come across a source like this (similar SDSS colors etc, similar radio contours, etc), how would we (or rather, I) have rated it, in terms of "spirals associated with doublelobes"? Certainly "fair", perhaps even "good" ... but certainly not "excellent"! 😄

I wonder what it looks like in WISE?

Boilerplate: Background "Luptonized" image produced from DSS2 FITS files (derived from B, R, and IR plates) obtained from SkyView with Python code described in this RGZ Talk post. VLSSr (red) contours derived from the FITS file produced using SkyView with Python code described in this RGZ Talk thread. Image center (J2000.0) is the radio source PKS 0400-181; "z_sp" the spectroscopic redshift of the (unnamed) foreground spiral galaxy (per NED).

Posted

• Another candidate to add: http://radiotalk.galaxyzoo.org/#/subjects/ARG0000xud -- one or two lobes? or nat?

This one really needs a good overlay with both FIRST and NVSS to see what's going on. In FIRST it looks one-sided but considering NVSS as well it's not clear if it's a nat or a doublelobe with a different host to the disk SDSS J124127.34+435147.1 Z_sp=0.149. Even if it is a double, the best-fitting optical match would then appear to be the non-ETG, non-QSO, object SDSS J124122.83+435201.6 Z_ph~0.13-0.16. To my eye, the radio emission seems more likely to be one-sided and to come from SDSS J124127.34+435147.1 which has a starburst spectrum according to SDSS.

Posted

• Worth to be checked

And

Posted

• by ivywong scientist, admin in response to JeanTate's comment.

Hi Jean,

Yeah, we are somewhat limited by the shallow surveys. Guess that is why radio can be such a goldmine because our more luminous sources actually tend to be higher redshift objects (which are mostly not visible at shorter wavelengths).

Given that these galaxies are barely resolved, it is tough to decompose the bulge/disk components or even create a sensible radial profile without washing out all the subtle features that our eyes can pick out.

WISE has a worse angular resolution compared to SDSS 😦 My opinion would be to rate this candidate as OK since we can actually make out some non-smooth structure which may or may not be spiral arms. It's ellipticity also helps.

To confirm, we'd probably need to borrow someone's 2-4m telescope and go deep on this object. If we can get 1arcsec or sub-arcsec resolution, we might be able to see more.

Posted

• Thanks Ivy.

My post was a brief write-up of a 'sanity check': from the link in your earlier post (that I was responding to), and the papers which cite it, we know the host of the radio emission is not the z_sp 0.037 disk/spiral galaxy, but a background z_sp 0.341 elliptical. At DSS2 and VLSSr resolution, how would we rate this object?

One thing I have not yet attempted (well, not in any serious or systematic way) is to see if the radio centroids are offset from the optical nuclei, for core/core-jet/triple/etc sources; if they are, then we more likely have an unrelated source. Of course, this doesn't work if the radio source is a doublelobe ...

The point about trying an overlay on WISE (or a WISE overlay, etc) is to see if the true host - the background elliptical - shows up as obviously offset (or whatever).

Posted

No worries Jean! Sanity checks are very useful even if sometimes they do turn into "insanity" checks as we approach the limit of diminishing returns.

Spatial offsets between radio and optical sources are only good if we know for a fact that the source is not a radio lobe (which we usually don't). One way (now the other scientists can add to this) to investigate the emission further is to explore the radio "colour" or the spectral index of the radio emission. For this, we would require quasi-simultaneous observations at a few radio frequencies (much like in the optical). From the spectral index and the radio luminosity of the sources, we can have a better constraint on whether the emission is star-formation dominated or AGN-dominated.

Unlike the optical observations, we would in an ideal world require quasi simultaneous observations because radio jets and lobes fade with time so the inferred colours would not be accurate if the different bands were taken several years apart.

I know this does not help you too much but I thought it might be interesting to you 😃

Posted

• Another 'status note':

• two periods I need to check: 18 June to 22 July, 23 August to now
• I expect to have at least one FIRST/NVSS/both contour-overlay-on-SDSS image for ~90+% of fair/good/excellent candidates by tomorrow (excluding those identified in the two periods above)
• some work to speed up creation and posting of overlay images
• several in parallel/independent investigations:
• historical sanity checks (DSS2 and/or WISE as base image; possibly other radio surveys as contour overlays)
• Quench Project objects
• criteria for assessing candidates, other than 'host NOT a boring elliptical' (etc)

I have been in contact with several (radio) astronomers, by email, as well as some fellow ordinary zooites, concerning how to progress this research.

For what it's worth - which isn't much - the total number of excellent/good/fair candidates in my database is over 60.

Posted

• Thanks Ivy! 😃

It is, in fact, very helpful. I think it's fair to say that, as far as I know, I am the only person actually researching the candidates posted in this thread (I am aware that some individual objects are being looked at, by others). So if this work is to end up as a paper some day, I should knuckle down and learn about 'radio colors', and see what I can find in terms of observations made at other radio frequencies (even if they're not 'quasi-simultaneous' 😉).

Posted

• I expect to have at least one FIRST/NVSS/both contour-overlay-on-SDSS image for ~90+% of fair/good/excellent candidates by tomorrow (excluding those identified in the two periods above)

There are, as of now, just two such candidates without such an image, and one of those is because it's outside the SDSS footprint (so it's 'yet to be rated', rather than 'fair/good/excellent').

For what it's worth - which isn't much - the total number of excellent/good/fair candidates in my database is over 60.

Leaving aside objects in the two periods I need to check properly (18 June to 22 July, 23 August to now), I have 72 excellent/good/fair candidates:

• excellent: 12
• good: 23
• fair: 37

(almost linear; coincidence?)

Posted

• An update: I think I'll abandon trying to check objects posted in comments in the period 18 June to 22 July. For the rest, I'm now up to date with checking; here's the tally:

• excellent: 13 (7/6)
• good: 30 (16/14)
• fair: 47 (22/25)
• TOTAL: 90 (45/45)

The numbers in brackets are (the number with spectroscopic redshifts (mostly, but not wholly all SDSS)/the number with photometric ones (all SDSS)).

Combining excellent and good ("e+g"), and binning by estimated redshift (making no distinction between z_ph and z_sp), four bins: 0.000 to 0.099/0.100 to 0.199/0.200 to 0.299/0.300 and over, the numbers are:

e+g  5 15  9 14
fair 7 14 13 13
Tot 12 29 22 27


Broken down by z_ph (first block of four columns) and z_sp (second):

e+g  0  5  6  9 /  5 10 3  5
fair 2  8  9  6 /  5  6 4  7
Tot  2 13 15 15 / 10 16 7 12


Analyses using inverse concentration ratio, fracDeV, and ellipticity next.

And I hope to keep up with checking for new candidates as either I find them, or others post them.

Posted

• I'm going to make sure all 15 'excellent' or 'good' candidates are checked out as best I can: overlay image, inverse concentration index, ellipticity, GZ1 and GZ2 morphology votes, ...

There are now 45 'e+g' ('excellent' or 'good') candidates; I have posted overlay images, obtained the values of the relevant photometric parameters from SDSS DR10, and calculated inverse concentration index and ellipticity for each.

What are the results?

Before getting to them, a quick summary of the three photometric tests I plan to use*:

1. Ellipticity (reference, Buta 2011): 0 to 3 means 'consistent with being an elliptical'; 4 is borderline; 5 to 9 means 'inconsistent with being an elliptical' (or at least a giant or normal elliptical; there are E5 and maybe even E6 dwarf ellipticals). Here are some examples (r band values):

0

4

7

1. inverse concentration index (c) (references, Strateva+ 2001 and Shimasaku+ 2001): less than 0.385 is consistent with being an elliptical; otherwise not. Here are some examples (r band values):

0.313

0.386

0.427

These two tests work best in tandem; for example, if the ellipticity is inconsisent with being an elliptical, c won't be very informative. For example:

ellipticity 7; c 0.329

1. de Vaucouleurs profile factional likelihood, fracDeV (I don't have a reference yet, other than this SDSS webpage): naively, fracDeV > 0.5 means consistent with being an elliptical; however, disk galaxies with large bulges and those with prominent bars may have fracDeV values as high as 0.9, even 1. Also, the way this parameter is calculated, values for bands other than r are, um, less helpful. Here are some examples (r band values):

1.00

0.58

0.23 (surprising, eh?)

One reason why this last test isn't so helpful for us is that an obvious AGN can make the value pretty meaningless. Why? Because the value is based on comparing two (actually three) single-component model fits, and an obvious AGN means at least two components should be modeled**. Here's a good example:

The r band fracDeV value is 1.00; yet it is a barred red spiral, not an elliptical! 😮 Obviously.

Obvious AGNs also mess up inverse concentration index values - they make disk-like galaxies into ellipticals (i.e. reduce c to below 0.385). This galaxy is a good example; it has an r band c of 0.311.

No surprise that there are rather a lot of obvious AGNs among the 45 e+g candidates (and among the 48 fair ones too). In fact, an obvious AGN strengthens the case that the candidate is host to the apparently associated double lobes, doesn't it?

One last example, just for fun; what would you guess are the ellipticity, c, and fracDev r band values for this fave of 42jkb? (the r band is mapped to G in these RGB JPEG images):

*a fourth photometric test - colors - is one I do not plan on using; why not? you have only to ask 😉

**this is also why it fails for disk galaxies with big bulges (which are, obviously, two-component systems); why it fails for strongly barred disk galaxies is a bit more complicated. The third model is a PSF (point spread function), which is helpful for this work only for testing if the blob (galaxy) is, in fact, not at all like a PSF

Posted

• raynorris, in a post in the Journal Club thread Paper on Giant Radio Jets from a spiral just appeared on the preprint server yesterday....., added some important pieces to the SDRAGN puzzle. Or at least the puzzle of what sort of candidate host might the definition of "spiral" include. Here's what he wrote:

Speak to most astronomers and they will tell you that "radio-loud quasars are never found in spiral galaxies," A select few of us, including you and me, know they're wrong, but actually they're only a bit wrong - the vast majority of radio-loud quasars (or, more broadly, active galactic nuclei - AGN) are NOT in spirals. Which is why finding a pile of them in RGZ is so exciting.

It's taken me quite a while to get my head around the central question of "what sort of host are we looking for again, exactly?" - and I'm still finding it confusing - but this stark bimodal distribution (radio loud? host cannot be a spiral!) seems to key.

Here are some pieces, as I now understand them (of course, this will surely change, as I surely have misunderstood lots):

• "Seyferts" are a red herring ... they're just AGNs; if the candidate host we are considering has an AGN, so much the better. How to tell if there's an AGN? If the spectrum - one where the aperture covers the nucleus - is classified as Seyfert, or AGN, or Composite (in a BPT diagram), then AGN. If there's no spectrum but the center of the galaxy is very bright and point-like, it's an AGN.

• LINERs and AGNs 'currently' in the 'off' state? Dunno

• "doublelobes" are also a red herring ... they're just the most reliable marker (here in RGZ) of 'radio loud'. Presumably a galaxy with a radio loud nucleus, even a point radio source, would be a candidate SDRAGN (i.e. we would just need to decide if the host is a 'spiral'). This helps me a lot; among other things, I've been wondering why we'd exclude SDRAGNs whose jets were pointed more or less straight at us (so we wouldn't see two distinct lobes)

• doublelobes are also a red herring from another perspective: faded radio emission, hybrids, etc are just as good - in terms of finding SDRAGNs - because they are markers of past radio-loudness

• this one I already knew, but it's worth repeating: by 'spirals' we mean 'disk galaxies' ... spiral arms, bars, etc are important because they occur only in disk galaxies. However, plenty of genuine disk galaxies lack such morphological features (at least as seen in SDSS images), hence the importance of using other tests

• significant on-going star formation is also a red herring ... at least in terms of selecting candidates (though the extent of star formation in genuine SDRAGNs is a topic of great interest, of course). So red spirals are just as interesting as the classic blue ones

• while not, strictly speaking, part of the hunt for Red October SDRAGNs, finding radio loud blue ellipticals or irregulars would be perhaps even more dramatic (but see next)

• what to do, then, about candidate hosts which are interacting/merging galaxies? This is, for me, today, perhaps the biggest open question. A lot of the > 90 e+g and fair candidates seem to show signs of interacting or merging; but when does a host stop being an SDRAGN and start being an MDRAGN? Perhaps our project might be called 'How common is S&M among DRAGNs?" 😃

Posted

• Applying the three tests - ellipticity*, followed by inverse concentration index and fracDeV (r band only in all three tests) - blindly, here's the breakdown ("e+g" means "a rating of excellent or good"):

E   0-3  4 5-9 Tot
e+g  25  5  14 44
fair 17 10  20 47
Tot  42 15  34 91


So that's 34 SDRAGN candidates - 14 e+g and 20 fair - which are unlikely to be ellipticals (i.e. E > 4). Examining the remaining 57:

c 0-0.385 else Tot
e+g    19  11  30
fair   14  13  27
Tot    33  24  57


24 SDRAGN candidates among these 57; 11 e+g and 13 fair.

Lastly, fracDeV:

fracDeV 0-0.5 0.5-0.7 0.7-1.0 Tot
e+g       8       4      18   30
fair      6       4      17   27
Tot      14       8      35   57


Among the 33 candidates which 'fail' the inverse concentration index test, how many have obvious AGNs? Ditto for the 43 which 'fail' the fracDeV test? Stay tuned! 😃

*there are two sets of r band photometric data that can be used, those derived from fitting a de Vaucouleurs profile and from fitting an exponential profile. I used the former, but using the latter makes almost no difference to the numbers, though several galaxies 'swap places' when the latter parameter is used; I'll write these up later.

Posted

• This is a lot of work you've put in @JeanTate so nice going! I have a question, though: how does interaction/merging affect the different criteria? It can be hard to tell what the original galaxy types may have been in some of these cases, especially those without spectra, and interactions might sometimes result in spiral features due to tidal interaction even if both were originally typical ETGs. Are there any SDRAGN candidates that are clearly not interacting and how does their e, c and fracDeV differ from those that are?

I find it very encouraging that so many of the fair candidates are also meeting the criteria, however the usual caveat must be applied that further observations are needed to be sure they are genuinely the host galaxies of the observed radio emission and not just a chance superposition. Some of these are rather faint - a lot of observing time on different telescopes is going to be needed to settle this question.

In the meantime, I imagine the scientists might be asking which objects are conclusive enough from the existing data to be collected together and published in a paper, whilst seeking further observations at the relevant facilities. My guess is that those excellent and good candidates with spectra would have the best chance of qualifying, so the metrics you've been applying in gathering this sample up until now are still useful - having multiple pairs of eyes looking at the different sources and checking they are well-aligned with the candidate host, show spiral features etc. still makes for a useful check.

Given the small number of known objects, this has the potential to be an absolutely massive paper, which makes it even more important to do it right and to make the case for each candidate galaxy with whatever observations are required. This kind of telescope time is not easy to come by, so perhaps a poster for a conference would be a good place to start? With an abstract in published conference proceedings, this would be a good way of highlighting the potential for this research (especially to the Time Allocation Committees of the needed observatories) and attracting collaborators with access to good facilities. What are the Scientists' views on this?

Posted

• Among the 33 candidates which 'fail' the inverse concentration index test, how many have obvious AGNs?

9 (8 e+g, 1 fair). Of the rest, 8 I rate as 'maybe' (4, 4).

Ditto for the 43 which 'fail' the fracDeV test?

10 (9, 1). Of the rest, I rate 12 as "maybe" (6, 6).

Now back on 19 September, I wrote "For the rest, I'm now up to date with checking; here's the tally: [...] TOTAL: 90 (45/45)" Yet in the table above I have 91 (44/47); how come?

In fact, the database I used for the above analyses has 92 candidates; yes, there were some additions after 19 September, and one change in rating. The one 'missing' candidate is in SDSS DR7 but not DR10; as my analyses are based on DR10 photometric data, I had to exclude one candidate. 😦

Of the 91 SDRAGN candidates in the above analyses, 44 have SDSS spectra; what is the distribution of the automated SDSS spectroscopic pipeline's classifications? Stay tuned! 😃

Posted

• Thank you WizardHowl. 😃

I have a question, though: how does interaction/merging affect the different criteria?

If the Zooniverse had already developed an easy-to-use classification engine (as has been mentioned quite a few times), or if waveney were still around and could modify his Irregulars Project tool, we could run a quick exercise, getting eyeballs on the ~100 SDRAGN candidates*, and so robust estimates of morphological features such as "tidal tails", "shells", "disruption" (of course, the prep work would take quite a while!). I ran just such an exercise myself, on a small sample of my Huds candidates, via the GZ forum's PM system with a small number of volunteer zooites; it was pretty intensive (read this Zooniverse Letter for some details).

But we don't have any of those options - and I have zero trust in Talk's PM system anyway - which leaves ... what?

I find it very encouraging that so many of the fair candidates are also meeting the criteria,

Although I don't think I had any concrete expections going in, I was quite delighted to see that Ne+g and Nfair have remained ~equal, as the number of candidates has grown. It's also quite interesting that the distributions - by almost any criteria - are also ~the same (I do plan on running some chi^2 tests, and I have a huge number of other parameters to look at). Two parameters whose e+g and fair distributions differ are z and magnitude; while more or less expected, it's nice to see it there in the data.

however the usual caveat must be applied that further observations are needed to be sure they are genuinely the host galaxies of the observed radio emission and not just a chance superposition.

Well, various cuts can be made even now, to focus on just the very 'best' candidates (something I plan on doing). Then there's further observations and further observations ... for a significant fraction of the candidates, deeper radio observations would very likely quickly strengthen the SDRAGN case (or disqualify it). Ditto higher resolution radio observations. Besides, there are plenty of online datasets to check; perhaps there's a Hubble image which captures one of our candidates? Something I have on my ToDo list ...

What are the Scientists' views on this?

I wonder too. From raynorris' post earlier today, just four SDRAGNs have been reliably discovered/observed to date; what advice do they have for dealing with ~100 new candidates?

*one of my ToDo items is estimate the rate at which e+g/fair candidates are being found; if RGZ runs for another ~nine months, we could easily have ~200 candidates by the time it's over 😮 😮

Posted

• Of the 91 SDRAGN candidates in the above analyses, 44 have SDSS spectra; what is the distribution of the automated SDSS spectroscopic pipeline's classifications? Stay tuned! 😃

As follows (I have omitted "GALAXY" in front of all but the GALAXY class; not all classes have this 'prefix'):

SDSS class              e+g fair Tot
AGN                       4  4    8
QSO AGN BROADLINE         2  0    2
QSO STARBURST BROADLINE   1  1    2
QSO STARFORMING BROADLINE 0  1    1
STARBURST                 2  1    3
STARFORMING               5  3    8
GALAXY                    6 10   16
Total                    23 21   44


Collapsing this down to just three classes, "AGN" (top seven classes), STARRY" (STARBURST and STARFORMING), and "BORING" (GALAXY alone):

class   e+g fair Tot
"AGN"    10    7  17
"STARRY"  7    4  11
"BORING"  6   10  16
Total    23   21  44


What is the distribution of SDSS spectral classes among the morphological classes? Specifically:

• the 34 E>4 candidates?
• the 25 (of 57) with c>0.385?
• 'obvious AGN' among the 33 (43) which 'fail' the c (fracDeV) test?

Stay tuned! 😃

Posted

• What is the distribution of SDSS spectral classes among the morphological classes?

There are 11 (of 34) E>4 SDRAGN candidates with SDSS spectra, 4 of which are e+g. These 4 are 2 "STARRY" and 2 "BORING". Of the 7 fair, there are 3 "STARRY", 2 "AGN", and 2 "BORING".

Of the 11 (E<5 AND c>0.385) SDRAGN candidates (6 of which are e+g) with SDSS spectra, there are 4 "AGN" (2, 2), 4 "STARRY" (3,1), and 3 "BORING" (1,2).

22 of the 34 (E<5 AND c<0.385) SDRAGN candidates (13 of which are e+g) with SDSS spectra, there are 11 "AGN" (9,2), 2 "STARRY" (2,0), and 9 "BORING" (3,6).

Of these 11 "AGN", I rated 6 as having an "obvious AGN", 2 as "maybe", and 3 as "no". Of the 2 "STARRY", I gave 1 a "maybe" and the other a "no". And the "BORING"? Just 2 "maybe" (7 "no"). At the 0-th level, eyeballing works. So it would not be totally wild to accept my eyeball 'obvious AGN' ratings for the SDRAGN candidates without SDSS spectra.

The point of all this analysis - well, one point - is to be able to categorize SDRAGN host candidates by an objective method, one which does not depend on this one ordinary zooite's visual classification*.

So, envelope please ... drum roll ... and the winners are ... (did you guess "Stay tuned! 😃"? 😛)

*whether the candidate hosts are, in fact, hosts of the observed 'doublelobes' radio emission is a separate question; I intend to have a go at semi-quantitative analysis on that topic later.

Posted

• At 18 June, 2014, I estimated the rate of discovery of 'doublelobes associated with spirals' candidates to be ~15 per month.

[...]

On its face, the discovery rate would seem to have picked up greatly, especially considering that I have not yet checked 'Recent Object Comments' from 18 June to 22 July; however, a more useful metric would be the discovery rate of excellent/good/fair candidates ... stay tuned ... 😉

On 19 September (the last day I'm current to), there were 92 excellent/good/fair SDRAGN candidates. That's 276 days since RGZ kicked off (17 December, 2013 is the date I have). Which gives an average of ~30 SDRAGN discoveries per 100 days. Of the 92, 13 are 'precoveries'; candidates which were first posted earlier than the start of the period I checked. These are almost all objects (ARG fields) which someone added a comment to recently, but the first comment was further back in time.

From 18 June to 19 September, I added 61 excellent/good/fair SDRAGN candidates*, giving a discovery rate per 100 days of ~65. Two every three days, on average 😮

How much longer do we expect RGZ to run for? Yes, there will surely be a tailing off of discoveries towards the end, as the work becomes getting the minimum number of classifications for the last few thousand fields ...

But wait! There's more! 😛

Radio-loud spirals, ones whose radio emission does not appear - to us - like triple or doublelobes, or even hourglass. I haven't even had an eye out for these; have you?

*yes, there's some revisionism; it was only quite recently that I became confident the rating criteria were applied consistently across all candidates

Posted

RGZ is now about 1/4 completed so we are not even halfway through yet of this Phase 1 project so I'm afraid that there is still plenty to do.

Not all radio emission from a spiral is from an AGN so for the very nearby galaxies, we can see that the radio emission is actually tracing star formation along the spiral arms.

Mergers have long been associated with radio galaxies so mergers are definitely interesting as they are related to AGN evolution in some galaxies.

Posted

• I will drop this one here ( sorry if it was mentioned here )

see comment by HAndernach

SDSS J225513.21+143911.4 - 1237656496180560229

Posted

• Thanks! 😃

No, it does not seem to have been mentioned before, and I don't know how I missed it in my first search, where I checked everything Talk's Search tool found with the word "spiral" ... 😦

Posted

• I wonder what it looks like in WISE?

First, here's the VLSSr contour overlay on my Luptonized DSS2 image:

The bright pink in the center points to an AGN; however, at this resolution the background z=0.341 elliptical is not seen as a separate source from the foreground z=0.037 spiral, in either the DSS2 or WISE composite image.

Boilerplate: Background "Luptonized" image produced from (top) DSS2 FITS files (derived from B, R, and IR plates), and (bottom) WISE FITS files (3.4μ, 4.6μ, and 12μ bands), both obtained from SkyView with Python code described in this RGZ Talk post. VLSSr (red) contours derived from the FITS file produced using SkyView with Python code described in this RGZ Talk thread. Image center (J2000.0) is the radio source PKS 0400-181; "z_sp" the spectroscopic redshift of the (unnamed) foreground spiral galaxy (per NED).

Posted

• (L98) Lamer+ 1999 report observations showing the BL Lac object PKS 1413+135 is indeed the nucleus of the (local) disk galaxy

The host is z_sp 0.247 SDSS J141558.81+132023.7, and as it's in the SDSS footprint, straight-forward for me to produce a FIRST contour overlay on SDSS image. But first, the galaxy itself:

Wow! 😮 Look at all those contours (and the interval is √5, not the √3 I usually use). I'll see if this is in an ARG image; for now, here's one of the orange FIRST images:

So this is an SDRAGN*, but one where we're viewing the lobes end-on. I wonder how many of the SDRAGN hunters have seen objects like this, but not thought to comment on them? And as I understand only a small subset of compact radio sources is being selected for RGZ classification, how many lurk in some database somewhere, not yet seen by any human's eyes?

*well, I should apply the three photometric tests to it, if only to see how it compares with the SDRAGN candidates discovered so far.

Boilerplate: SDSS image per http://skyservice.pha.jhu.edu/DR10/ImgCutout/getjpeg.aspx, FIRST (red) contours derived from the FITS file produced using SkyView with Python code described in this RGZ Talk thread. Image center (J2000.0) is the galaxy SDSS J141558.81+132023.7; 'z_sp' its SDSS spectroscopic redshift.

Posted

• (L98 and V01) Emonts+ 2009 "We present new observational results that conclude that the nearby radio galaxy B2 0722+30 is one of the very few known disc galaxies in the low-redshift Universe that host a classical double-lobed radio source"

The host is z_sp 0.019 SDSS J072537.22+295714.7, and as it's in the SDSS footprint, straight-forward for me to produce a FIRST contour overlay on SDSS image. But first, the galaxy itself:

I'm not sure I'd've called that a doublelobe, but it is surely an SDRAGN, isn't it?

When I get time, I'll see if I can find if it is in an ARG image; in the meantime, an orange FIRST image:

Hmm, maybe there's more to this source, radio-wise, than just what's in the 1.8'x1.8' image above?

Boilerplate: SDSS image per http://skyservice.pha.jhu.edu/DR10/ImgCutout/getjpeg.aspx, FIRST (red) contours derived from the FITS file produced using SkyView with Python code described in this RGZ Talk thread. Image center (J2000.0) is the galaxy SDSS J072537.22+295714.7; 'z_sp' its SDSS spectroscopic redshift.

Posted

• Ledlow+ 1998 (L98) reports the discovery of 0313-192, an Eos associated with doublelobes

This is perhaps the most famous SDRAGN, not least because of a NASA PR which included a VLA overlay (not contours) on a Hubble image (source):

What do NVSS contours overlaid on colorized DSS2 and WISE images look like? This (note that the orientation of the NASA PR image is different):

Oh what a difference resolution makes!

Boilerplate: Background "Luptonized" image produced from (top) DSS2 FITS files (derived from B, R, and IR plates), and (bottom) WISE FITS files (3.4μ, 4.6μ, and 12μ bands), both obtained from SkyView with Python code described in this RGZ Talk post. NVSS (cyan) contours derived from FITS file produced using SkyView with Python code described in this RGZ Talk thread. Image center (J2000.0) is (48.9671, -19.1123); "z_sp" the NED spectroscopic redshift of the galaxy at that position.

Posted

• Véron-Cetty&Véron 2001 (V01) report the discovery of the association between NGC 612, an S0 (lenticular) and the FR II radio source PKS 0131-36

NVSS contours overlaid on colorized DSS2 and WISE images:

Boilerplate: Background "Luptonized" image produced from (top) DSS2 FITS files (derived from B, R, and IR plates), and (bottom) WISE FITS files (3.4μ, 4.6μ, and 12μ bands), both obtained from SkyView with Python code described in this RGZ Talk post. NVSS (cyan) contours derived from FITS file produced using SkyView with Python code described in this RGZ Talk thread. Image center (J2000.0) is (23.4906, -36.4933); "z_sp" the NED spectroscopic redshift of the galaxy NGC 612.

Posted

• (L98 and V01) Morganti+ 2011 not doublelobes, but "We present a detailed study of PKS 1814-637, a rare case of powerful radio source [...] hosted by a disk galaxy."

Too far south for NVSS (and FIRST), but SkyView has SUMMS 843 MHz data, so I used that to produce radio contour overlays on DSS2 and WISE images:

The host is clearly not an elliptical, though whether it's a placid spiral/disk galaxy or engaged in a merger cannot be easily determined from these images.

A notable feature of all four of my overlays on WISE is how bright the host is in the 12μ band, as can be seen by the pink/red color. That this is not a feature of galaxies in general can also be seen the fact that most of the other galaxies in the images are blue (well, perhaps not in the first; it's not obvious that there are other galaxies). This likely points to the existence of an AGN. An interesting exception is the 'nearly vertical' Eos in the last image; perhaps its strong pinkish-red color is due to a thick dust lane? PKS 0313-192 has a prominent dust lane too; maybe its strong 12μ band emission is due at least in part to that feature?

Boilerplate: Background "Luptonized" image produced from (top) DSS2 FITS files (derived from B, R, and IR plates), and (bottom) WISE FITS files (3.4μ, 4.6μ, and 12μ bands), both obtained from SkyView with Python code described in this RGZ Talk post. SUMMS 843 MHz (yellow) contours derived from FITS file produced using SkyView with Python code described in this RGZ Talk thread. Image center (J2000.0) is (274.8958, -63.7634); "z_sp" the NED spectroscopic redshift of the galaxy at that position.

Posted

• Thanks! 😃

RGZ is now about 1/4 completed so we are not even halfway through yet of this Phase 1 project so I'm afraid that there is still plenty to do.

And the number of SDRAGN candidates among the ~170k FIRST objects* we will eventually classify will certainly be far greater than ~400! 😮

At least, per the definition I've been using so far.

Why?

Because it is unlikely the (vast?) majority of zooites who do classify ARG images with SDRAGN candidates in them will either comment on the image, or start a discussion. And if there is no comment or discussion ("cod") on an image, avid SDRAGN hunters will not find them.

Consider this: only ~30 ordinary zooites (i.e. not counting scientists) have first cod-ed on any of the ARG images which I have (so far) in my candidate SDRAGN database** ; that's a trivial fraction of the, what, several thousand in the co-author list. Sure, a quite small number of zooites have each done many thousand classifications, and among those are surely several/most/all? of those with 10+ entries in my candidate SDRAGN database** (there are only six, so far).

Another factor: the time distribution of those zooites who first cod-ed on ARG fields in my candidate SDRAGN database** , and who have less than four such ARG fields, is***:

period Dec-Mar Apr-Jul Aug-Sep Total
number      15       5       3    23


But perhaps we can identify candidate SDRAGNs from the classification data, at the end of Phase 1 (whatever that is)? For example, from the WISE objects identified as host of DRAGNs, identify likely SDSS counterparts, and apply the three photometric tests (above) automatically, outputting a modest number to check manually?

Question for a member of the Science Team: is this feasible? If so, can we begin planning for it now?

*source: 42jkb "We have over 170,000 images in RGZ" on June 12 2014 6:58 PM, in the Anyone getting any repeat images? thread, p4

**the full one, not just the subset of e+g and fair

***for those with more than one ARG 'find' (there are just three), date of first find; not that it matters, all finds for such zooites are in the same period

Posted

• by 42jkb scientist, admin in response to JeanTate's comment.

HA! You found one of my favourite galaxies NGC 612. I'm working on this object right now with observations from the Australia Telescope Compact Array (ATCA). A work in progress. I presented this work at the GZ conference in Sydney. It is a rather dynamic system.

Posted

• Turning this analysis into a 'volume' one (and using the current 92 candidate SDRAGNs) ...

... but first, what's the redshift distribution of the 'known' SDRAGNs?

First, decide which objects are actually these! Here's what raynorris wrote (here):

In that paper we go through the published claims of spiral DRAGNS and conclude that we know of only four bona-fide spirals with radio-loud double-lobed AGN.

I'm not sure which are the four, so I'll flesh out the list with ones I found in the literature ('SDSS' indicates that it's in the SDSS footprint)*:

• B2 0722+30, z 0.019 SDSS
• PKS 0313-192, z 0.067
• PKS 0131-36/NGC 612, z 0.030
• Speca z 0.138 SDSS
• J1649+2635 z 0.055 SDSS
• J2345-0449 z 0.082 SDSS

That's five in 0<z<0.1, and one in 0.1<z<0.2.

Here's the distribution of the 92 (so far) candidate SDRAGN, by z_sp vs z_ph:

redshift 0-0.1 0.1-0.2 0.2-0.3 0.3+ Total
z_sp      12      15       8     12   47
z_ph       0      15      15     15   45
Total     12      30      23     27   92


That all the candidates in the lowest redshift bin have SDSS spectra is not really surprising, nor is the relative dominance of those without such spectra in the other bins (combined).

Now by e+g vs fair:

redshift 0-0.1 0.1-0.2 0.2-0.3 0.3+ Total
e+g        6      16       9     14   47
fair       6      14      14     13   45
Total     12      30      23     27   92


Similarity abounds.

Yes, because there are only six 'already known' SDRAGNs, statistical comparisons of the differences in the distributions is, um, not terribly helpful; however, that only 13% of the candidate SDRAGNs have redshifts less than 0.1, cf 83% of the known ones suggests a rather strong selection effect is at work.

And there is clearly also a selection effect at work in the candidate SDRAGNs: if SDRAGNs were distributed equally, by volume, out to z=0.3, you'd expect ~80 in the 0.1<z<0.2 range, and ~230 in the 0.2<z<0.3 one (based on having found 12 in the 0<z<0.1 range)**.

Assuming that the five already known z<0.1 SDRAGNs are all there are (clearly a far too conservative assumption), there should be ~35 in the 0.1<z<0.2 range.

From the radio perspective, SDRAGNs should be easily visible in the FIRST images of RGZ out to, what, z~0.5? 1? Certainly FIRST has the sensitivity to detect all known SDRAGNs out to {what}? However, its resolution may limit discoveries to {what}, right?

Optically the limits are a lot more severe, using SDSS images, so in one sense it doesn't matter what the FIRST limits are. I'll have a go, later, at estimating how far away (z) each of the known SDRAGNs in the SDSS footprint would likely be recognized as disk galaxies.

*excluding the radio loud 'point' sources associated with disk galaxies

**I've assumed flat Euclidean space, with no evolution; sure, these are unreal assumptions, but OK for the level of analysis here

Posted

• I'll have a go, later, at estimating how far away (z) each of the known SDRAGNs in the SDSS footprint would likely be recognized as disk galaxies.

Just for fun, I've 'moved' some already known SDRAGNs and some candidate SDRAGNs out to z=0.1. I've done this in a very simple, and one might say rather unrealistic, way; I changed the 'plate scale' in SDSS cutouts so that the 'on the sky' scale is the same, if the galaxies were at z=0.1. There are many reasons why this is unrealistic; however, in terms of the apparent size of the galaxies, and (to some extent) visibility of features, it's a good 0th level simulation.

B2 0722+30 J1649+2635

J2345-0449 114d

22jc 1xvf

2esi

And moving to z=0.2:

B2 0722+30 J1649+2635

J2345-0449 Speca

114d 1xvf

2esi 13o3

244x 1kwr

3pjj 2kvu

23wq

Interesting, eh?

B2 0722+30 J1649+2635

J2345-0449 Speca

114d 2esi

13o3 1kwr

2kvu 23wq

114d 0hga
318m

Some disk galaxies will likely not even be visible at z~0.3, much less recognizably 'spiral'; however some, especially Eos, are (likely) still quite recognizable even at z~0.3! 😮

I'll identify the galaxies later ... DONE

Posted

• Very cool! 😃

So, is this a confirmed SDRAGN, one of the four?

Posted

• So, envelope please ... drum roll ... and the winners are ...

Not actually a final list, but here are five very hot contenders*.

In ARG0000rn8, z_sp 0.096 SDSS J135152.97+465026.2, an ~Eos. Although fracDeV is 1.00, c is 0.338, and E 4, it's got 'pointy ends', which no elliptical has. Spectroscopically, SDSS calls it "STARFORMING", hah! I had this as "good":

Not a DRAGN, but likely (?) twin back-to-back jets emitted ~perpendicular to disk plane (at least in one dimension). They appear to have quite different strengths, perhaps because of Doppler relativistic beaming, perhaps due to an inhomegeous ISM.

In ARG0001iym, z_ph 0.1 SDSS J115259.71+332531.1 doesn't look much, but fracDeV is only 0.33, and c 0.416 (E is 3), so it's almost certainly not an elliptical. Believe it or not, I had this as "fair" (by eyeball alone, it's not at all clear - to me at least - that it's not an elliptical):

Unmistakable FR II radio source (I hope I got that right!), though the lobes are not even close to being equal in observed luminosity/flux; the bonus is the clear nuclear emission.

In ARG00023wq, z_sp 0.176 SDSS J120301.43+235319.9 illustrates well how a very bright nucleus can produce misleading values; fracDev is 1.00, c 0.327, and E 4 😮 Yet it's an obvious Eos, so no wonder I classed it as "excellent":

Beautifully symmetric (detached) double lobes, with the host right in the middle, and strong (nuclear) emission as well. With such a bright nucleus, no surprise that, spectroscopically, it's a "QSO BROADLINE". Case closed.

In ARG0003o4w, z 0.209 (per NED) SDSS J023832.67+023349.1 is similar, fracDeV 1.0, c 0.31, E 4, and a very bright nucleus; not quite as obviously an Eos (perhaps it's merely highly inclined). Another "excellent":

Quite asymmetric, semi-detached lobes, with an undoubtedly radio loud nucleus.

The last one may seem a very poor choice, but illustrates something about how powerful the three photometric parameters can be, as tests. In ARG0003a73, z_ph ~0.45 ( 😮 yes, you read correctly) SDSS J133538.98+073000.3 has a fracDev of 0.00, c 0.499, and E 8. Numbers which confirm what your eyes tell you anyway; this is an Eos. It too I had rated as "excellent":

Detached doublelobes, symmetrical in size and location if not in shape; and weak but certain nuclear emission (no purely starforming spiral would be visible in FIRST at a z of ~0.45, right?).

*r band parameters

Posted

@JeanTate: Thanks heaps for the nice number estimations. 400 and counting sounds like a great number to start with, For the low-z SDRAGNs, we will be able to pull host morphology from the eventual combination of of GZ+RGZ. However, we will have to contend with sample incompleteness for regions not covered by GZ/SDSS as well as disks galaxies at higher-z where WISE does not have the resolution to distinguish between disks or spheroids. Even then, I still think that this is an impressive effort. Well done all round!

Posted

The important point here really is that the limiting factor here for identifying SDRAGNs is not FIRST but with SDSS/WISE. Until we can detect and resolve the morphology of the host galaxy, the FIRST double lobed sources will just remain as double-lobed radio sources.

Posted

• Thanks. 😃

Depending on what we end up with, in the list of candidate SDRAGNs, it might be worth considering doing a separate, limited morphological classification exercise, using the hopefully-available-by-then Zooniverse Swiss Army Knife flexible off-the-shelf classification app.

Here's a suggestion for something which could be done 'now': from a cross-ID exercise, involving compact FIRST sources and SDSS galaxies (automated morphological identification, plus GZ2?), select a robust list of 'almost certainly associated' sources. Run the three photometric tests I described above, on the SDSS galaxies, and do some interesting cuts. Devise a metric which combines estimated z (for the SDSS galaxies, either z_sp if available or z_ph if not) and FIRST flux, apply, then rank. The ~100 (more? less?) galaxies at the top of such a list will surely include many radio loud spirals. It may even include some SDRAGNs, the ones which are triples.

What do you think?

Posted

• I did a calculation on the back of a very small envelope, on this.

Assume a flat, Euclidean universe, no k-corrections, no evolution, etc. At what redshift (as a measure of distance) would the FIRST PSF (5") be ~the same size* as a typical (non-dwarf, non-giant) galaxy? If that size is 20 kpc, then it's only ~0.2 ... a compact FIRST source could be from radio emission that extends (appears to extend*) beyond the optical boundary of the host galaxy at only z~0.2 😮

In SDSS images, some galaxies can be classified as morphologically distinct (i.e. other than 'roundish blob') out to z ~0.4, even beyond, even though their Petrosian radii are considerably smaller than the FIRST PSF (the only help WISE data could give for these would be to suggest the presence of an AGN, via the WISE colors). Certainly the most luminous galaxies - which includes the top x% of spirals as well as the giant ellipticals - are bright enough to be easily detected in SDSS - in the r, i, and (maybe) g and/or z bands - out to beyond z=0.4. Selection bias would be a nightmare to estimate ...

*this is projected size; in physical space two lobes could be separated by far greater distances, if viewed at a highly inclined angle

Posted

• by ivywong scientist, admin in response to JeanTate's comment.

Yes, I do have a paper planned for combining RGZ+GZ sources once the RGZ catalogue is further along the pipeline. The bulk of the work really is identifying the host galaxy. There are a few software these days that can do galaxy fitting and bulge-disk decompositions once we know where the hosts are. (eg. Galfit). Your suggested methods are also commonly used to infer "disky" structures so at some point, these may be used.

With respect to distances and angular diameters, cosmology starts kicking in and the diameters will no longer be straightforward. I refer you to http://adsabs.harvard.edu/abs/1999astro.ph..5116H for a quick reference on cosmological distances. Note that k-correction will start to impede as well at higher z.

Another reason why the next generation successor to the Hubble space telescope will be the James Webb Space Telescope which will mostly operate in the infrared.

Posted

• Maybe another candidate

SDSS J094953.45+071900.4 - 1237658491728363693

Posted

• Can't say how disky it is

SDSS J151353.96+241232.1 - 1237665178990149752

Posted

• Thanks very much, Dolorous Edd! 😃 I've added them both to my list, and will process them with the next batch (I've ~30 awaiting, not all candidate SDRAGNs*).

Teaching myself how to use TOPCAT, letting it loose on my downloaded copy of FIRST, and following up on something interesting WizardHowl discovered earlier:

To explain it properly would take me quite a while, and as it's very 'rough and ready' probably not really worth doing, but one way to look at it is as a crude radio luminosity function, of the e+g+f candidate SDRAGNs, compared with those of the Quench project Sample and Control objects. As it's normalized - very approximately! - to ARG0001xiw, the 'radio loud/radio quiet' divide is easy to see (if only as a vertical line, x ~0; the x-axis units are dex).

Now, about those systematics ... :p

*and I expect only ~half will end up being e+g or fair.

Posted

• by NGC3314

I'm a little late to this party - for normalization of Fint, does that mean something like radio/optical flux ratio scaled to SDSS 1649, or just a radio flux indicator scaled for redshift? (BTW, since there's lately a submitted paper on it and I don't know whether this point was ever discussed here - SDSS 1649+26 was the sole SDRAGN to emerge from a quick automated correlation between GZ1 morphologies and Kimball & Ivezi´c radio source catalog, blending NVSS and FIRST catalogs).

Posted

• Thanks! 😃

for normalization of Fint, does that mean something like radio/optical flux ratio scaled to SDSS 1649, or just a radio flux indicator scaled for redshift?

The latter, but done on the back of a very small envelope. 😛

BTW, since there's lately a submitted paper on it and I don't know whether this point was ever discussed here - SDSS 1649+26 was the sole SDRAGN to emerge from a quick automated correlation between GZ1 morphologies and Kimball & Ivezi´c radio source catalog, blending NVSS and FIRST catalogs

As you can see from this thread, Minnie sent me a copy, in confidence. The object itself, SDSS 1649+26, was first mentioned by zutopian, in the (now closed) GZ forum, here. It's also discussed, in several posts, up-thread (on p8, for example).

I calculated Fint by summing the values for Fint for the three FIRST sources (core and the two lobes) associated with SDSS 1649+26, in the FIRST catalog. One of the things I'm doing now is trying to get realistic estimates of L1.4GHz* with methods currently used in radio astronomy. And adding the Fints of lobes beyond the small radius of my initial search/match, for all 92 candidate SDRAGNs (and the seven ~SDRAGNs** mentioned in the literature, at least those within the FIRST/NVSS footprint).

*or perhaps P1.4GHz, following Morganti+ (2011), a source I found by following the 'cited by' in a paper Ivy mentioned (on p10 of this thread)

**they're not all SDRAGNs, not even all DRAGNs, but they all have estimated L1.4GHz (well) above an oft-mentioned threshold (~1023 W Hz-1)

Posted

• With Ray Norris' help (see this thread), I have been able to calculate L1.4GHz for the integrated radio emission (as detected by FIRST) within 30" of the SDSS positions of the candidate e+g+f SDRAGNs*.

From the FIRST data, I calculated L1.4GHz (the radio luminosity) as 7.2x1023 WHz-1 for J1649+2635 (FINT sums to 102 mJy, in FIRST). Rescaling all the radio luminosity estimates to this value (i.e. taking J1649+2635 as 1.00), here's a revised version of the above plot (with just candidate SDRAGNs; I'll add the QS and QC objects later):

*assumed to be the nuclei, but there may be some offsets

Posted

• I'm learning about TOPCAT and how it can produce matches of objects in large FITS files. Early days yet, but readers of this thread may enjoy this (yes, it's poorly labeled):

The x-axis is the estimated probability of an (SDSS DR7) object being an elliptical, as decided by an automated routine (Huertas-Company+ 2011); the y-axis the estimated integrated radio luminosity, from all FIRST sources, within 10", in a 71/27/73 ΛCDM universe, and SDSS spectroscopic redshifts*. In units of 1022 WHz-1 (so any galaxy above ~10 is kinda loud, and above ~100 is certainly loud).

I had hoped that this exercise might identify some disk galaxies with L1.4GHz nuclear emission well above 3*1023 WHz-1, and the plot certainly suggests there might be quite a few! 😮

However, many of the promising-looking candidates are mergers (some with strong AGN, per their spectra), some are artifacts or confusion. Here's one:

The galaxy in the center is z_sp 0.120 SDSS J103801.10+414554.3:

It's not a good candidate; it's somewhat distorted, possibly in the early stages of a merger; it's not loud (L1.4GHz only ~8*1022 WHz-1); and so on. Even its extended radio emission seems more likely to have come from the disk than any jets or lobes; certainly no sign of any giant, detached double lobes.

But as I said, it's early days; the area of sky from which the matches were obtained is only ~a few percent of the combined FIRST/SDSS footprint ...

UPDATE: I replaced the plot with one which includes the ~25 'match NVSS source only' galaxies. And added the reference

Also, just for fun, z_sp 0.186 SDSS J103932.12+461205.3:

Its probability of being an elliptical is only 0.03, yet L1.4GHz is ~3*1024 WHz-1 😮

In addition to the (very) radio loud nuclear emission, there's a hint of ... well, of something well away from the optical boundary. Is it a faded lobe? an artifact (don't think so; there's definite NVSS emission)? unrelated?? (Later, I'll see if I can find an ARG ID)

What do you think?

*actually, not exactly (I cut a few corners)

Generic boilerplate: Background image is either SDSS per http://skyservice.pha.jhu.edu/DR10/ImgCutout/getjpeg.aspx', or a "Luptonized" image produced from either WISE (3.4μ, 4.6μ, and 12μ bands) or DSS2 (derived from B, R, and IR plates) FITS files obtained from SkyView with Python code described in this RGZ Talk post. FIRST (red) and/or NVSS (cyan) contours are derived from FITS files produced using SkyView with Python code described in this RGZ Talk thread. The image center (J2000.0) is the SDSS galaxy SDSS J103801.10+414554.3
(top) and SDSS J103932.12+461205.3 (bottom); z_sp (z_ph) the spectroscopic (photometric) redshifts.

Posted

• Is this candidate too late for the party?

http://radiotalk.galaxyzoo.org/#/subjects/ARG00021ox -- hourglass, host edge-on shape with red bulge but blue-ish extensions

There is a spectrum, classed as GALAXY, and Z_sp=0.505. If this is a disk, it must be quite large but I suppose at this resolution it could instead be a late-stage merger?

EDIT (14:01 11/10/2014): host galaxy is SDSS J152931.73+244748.0

Posted

• It's never too late! The more the merrier!!

I've added this to my list/database, and will check it out when I run the next batch. But whatever this is, it looks really cool! 😃

Posted

• Thanks, here's another candidate, not quite so distant but also looking edge-on (SDSS J113231.69+250352.7 Z_ph~0.31-0.36)

http://radiotalk.galaxyzoo.org/#/subjects/ARG00020z4 -- asymmetric doublelobe, host looks like edge-on disk, including colour

I'm wondering if there's a selection effect that's going to appear at longer redshifts that favours identifying edge-on disks. They are faint enough that if they were face-on the images might only show the bulge region and the rest of the disk would be lost in the noise, whilst seen at other angles they might be barely distinguishable from ellipticals, with only the colours a clue - unless they were so huge that spiral arms were visible. If the sample of SDRAGN candidates with redshifts above, say, 0.25 shows a high proportion of edge-on objects then that would mean that there are more out there in the images but not resolved enough to identify them as such. Perhaps plotting the proportion of edge-on cases by Z (binned or otherwise) might shed some light on how many could be out there?

Posted

Very interesting @JeanTate! Confusion is certainly a factor but would you say that of all the the radio loud spirals you found, are they all part of a merger system or appear to be interacting?

Posted

• Trying to characterize the likelihood of merging/interaction, in any robust quantitative fashion, is impossible (IMHO).

One of my ToDoList items is to look into this, perhaps by putting objects into a ranked list. One of the Zooniverse projects - like Sunspotter, but for galaxies (I can't remember which one, just now) - used crowdsourcing to do this sort of ranking: present classifiers with a pair, and ask which shows more signs of merging/interaction. With enough independent classifiers (zooites), you'd get a very clean ranked list. Of course, to be of value, you'd need to run some tests on the questions asked, how the interface is designed, etc ... we already know these can have a quite significant effect on the outcomes*.

In any case, we already know that at least some of the best candidate SDRAGNs/radio-loud spirals show no signs of merging/interaction (and some do, of course); see the FIRST contours overlaid on SDSS images - our VERY BEST 'doublelobe spirals' thread, for example.

*side note: despite having had this confirmed very early on (the GZ mirror project, I think), it doesn't seem to have made it into the 'Things All Zooniverse Project Designers Must Incorporate' manual ...

Posted

Yes, I concur that many SDRAGNs/radio-loud spirals show no signs of merging/interaction but I was just wondering 😉 Mergers are certainly easier than interactions to determine because one would presumably see more than 1 "core" (as with the Antennae Galaxies or the Mice etc...) Interactions would require one to see strong warps/asymmetries and/or tails/streams which may not be possible at the depths that SDSS/WISE have probed. Anyway, it's food for thought. Great work again @JeanTate!

Posted

• SDSS J131357.69+642554.7 - 1237654610144526358

Uncertain - morphology

Posted

• Thanks; added to my list of 'to be checked'.

I now have ~50 on that list, and plan to start working through them soon. Based on the past, ~20-25 of these will turn out to be fair or e+g; however, I don't think there'll be any rated as excellent (I usually notice these as they come in; I don't recall any of the ~50 being particularly striking).

Posted

• Here's one, a new candidate which I rate as excellent, which is an excellent example of a 'not a boring elliptical' which is also an obvious post/ongoing merger (here for details):

Posted

• I now have ~50 on that list, and plan to start working through them soon.

First pass done (does not include applying criteria such as inverse concentration index, or ellipticity); here's the DRAFT breakdown:

• 6 e+g
• 25 fair
• 26 poor/not
• 2 "needs more work"
• Total: 59

So the ratio of e+g+fair to total "to be investigated" is ~the same; however, there are considerably fewer e+g (proportionately).

At a very approximate level, the rate of discovery (e+g+fair only) has remained at least the same, and possibly increased.

Now a request for help: with well over 100 candidate SDRAGNs, I need a more robust way to try to ensure the criteria I use - at this initial stage - are applied consistently. Ideally, I'd like to have a way to present images (or perhaps pairs of images) to my fellow zooites (or at least some group of you), and have you make judgements/assessments. Those assessments would then be used to classify the candidates more robustly, possibly even to rank them all, by each of ~five criteria. Not only would this greatly strengthen this work, but it would also provide a more certain basis for assigning 'poor' ratings (as it is now, I worry that some fairly good candidates get dropped - rated 'poor' - inconsistently).

Posted

• by ivywong scientist, admin in response to Dolorous Edd's comment.

I think this is reaching the limit of SDSS's ability to resolve morphology....

Posted

• And, frustratingly, the photometric test results can be summed up "borderline" or "ambiguous" 😦

SDSS J131357.69+642554.7 is an E4 (ellipticity), has a fracDeV value of 0.8, and an inverse concentration index of 0.39 (all r-band); putting error bars on these won't help either 😦

There is little doubt, however, that it's the host:

Generic boilerplate: Background image is either SDSS per http://skyservice.pha.jhu.edu/DR10/ImgCutout/getjpeg.aspx', or a "Luptonized" image produced from either WISE (3.4μ, 4.6μ, and 12μ bands) or DSS2 (derived from B, R, and IR plates) FITS files obtained from SkyView with Python code described in this RGZ Talk post. FIRST (red) and/or NVSS (cyan) contours are derived from FITS files produced using SkyView with Python code described in this RGZ Talk thread. The image center (J2000.0) is the SDSS galaxy SDSS J131357.69+642554.7; z_sp (z_ph) its spectroscopic (photometric) redshift.

Posted

• Now a request for help [...]

How about this: if a candidate host has radio emission co-inciding with its nucleus, it gets an 'A' for the test "is this galaxy the host?". And to make that call, how about having a pair of images, side-by-side: both have the same size (in pixels) and scale (in "/pixel); one is the 'straight' SDSS image, the other has a FIRST overlay.

Of course, this is just one criterion; there must also be "double lobes", and the host must be a "spiral". The former I'll address later; the latter? Well, the SDSS image should tell its own tale, and it should be fairly straight-forward to add the 'photometric test results' to the display* (e.g. fracDeV, ellipticity, inverse concentration index, asymmetry, GZ classification, and so on).

Sorta like this (it's only a DRAFT, and the Python code may not yet be working as I intend):

What do you think?

Generic boilerplate: Background image is SDSS per http://skyservice.pha.jhu.edu/DR10/ImgCutout/getjpeg.aspx. FIRST (red) contours are derived from FITS files produced using SkyView with Python code described in this RGZ Talk thread. Physical scale bar (cyan) represents projected distance at a redshift of z_sp/z_ph (lime), assuming a ΛCDM cosmological model with parameter values of ΩM 0.27, ΩΛ 0.73, and H0 71 kms-1Mpc-1. The image center (J2000.0) is the SDSS galaxy [...]

*Or not; may be quite a challenge, in Talk

Posted

I think it looks fine as the pair that you presented. The important thing about separating your objects is to be clear with your definitions. For example: you can choose to define spiral galaxies as galaxies with visible spiral arms. For quantitative parameters such as ellipticity and asymmetry, there will be confused cases.

Posted

• Thanks.

I'm starting with just one feature, whether the candidate galaxy has nuclear radio emission (at least as far as we call tell, from the FIRST data).

Consider these three:

Unambiguous, right? Nuclear radio emission in the first two, but not the third.

The image(s) in this post was (were) created from sources, and using methods, described in this RGZ Talk post. The object(s) at the center(s) of the image(s) is (are) {X}.

Posted

• Possible candidate

SDSS J161157.36+073856.1 - 1237662636376785646

Posted

• Jean 😃

I think the two final images there can only be described at this point as 'unclear' ... the resolution of the radio n the optical are good enough that it shouldn't be a resolution issue and remember that radio emission can be seen right out from the edge of the universe cos the wavelengths are long and don't suffer from dust extinction and the like! (w00 radio rocks 😄) ... so it's possible that the 'optical host' may be undetected / a background source... of course it is also possible that the emission is from the spiral/not-elliptical ... but i think you would need more data to check this!

Posted

I second @mini.mintaka's comment. Follow-up observations are necessary for further verification of the last 2 cases. In the first of the last 2 cases, one is able to conclude that the bulk of the radio emission is clearly not centred on the nuclear regions of the galaxy so the nuclear emission is not dominant in the observed emission.

Posted

• Thanks! And thanks too to ivywong! 😃

In the first of the last 2 cases, one is able to conclude that the bulk of the radio emission is clearly not centred on the nuclear regions of the galaxy so the nuclear emission is not dominant in the observed emission.

And, originally, 'extends beyond the optical boundary of the galaxy' was my #1 criterion 😉

i think you would need more data to check this!

I think this applies to every one of the 'fair' candidates, and to at least some of the 'good' ones too! In a way, the end result of this SDRAGN hunt is becoming more like "here's a (very!) long list of interesting/good candidates", with just a handful being as good as Speca, say, or PKS 0400-181, based solely on SDSS+FIRST+NVSS.

(for everyone reading this, all the examples I've posted I rated as either 'fair' or 'poor' candidate SDRAGNs; those ratings include 'nuclear emission' as just one criterion).

Anyway, more "how certain can we be, given just this data, that there's radio emission from the nucleus?" candidates coming up. In particular, how likely is it that we can have more than three possible answers? I.e. go beyond, 'certain', 'certainly not', and 'uncertain'?

Then, maybe, I'll move on to "how certain can we be, given just this data, that the doublelobe/extended emission is directly associated with/comes from the galaxy in the center of the image?" 😄

@Dolorous Edd: added it to the database; I'll process it with the next batch

Posted

SDSS J144527.38+093218.3 and SDSS J160938.28+145307.7- looks like a triple in the NVSS image

Posted

• One to consider, for several reasons: is host a disk? is it green? or are the green areas ionised clouds (Voorwerp)?

http://radiotalk.galaxyzoo.org/#/subjects/ARG0003gy5 -- radio morphology is complex with lobes, a core and diffuse emission

The host is SDSS J095100.54+051026.7 Z_ph~0.12-0.16 and has a noticeable white-ish core and white colours similar to the nearby disk galaxies in the SDSS view. The green features are located opposite each other with respect to the core, so perhaps more likely to be ionised clouds than star formation?

In FIRST, the radio emission resembles a small but strong triple but there is additional diffuse emission. It is not clear if this might be due to precession of the jets or a sign of Xshaped emission and NVSS does not exclude either alternative.

Posted

• QSO according to spectrum

Uncertain - morphology

SDSS J154007.84+141137.1 - 1237668312164007978

Posted

• Another disk-like candidate, with a spectrum classed as GALAXY BROADLINE, but in neither face-on nor edge-on posture it's hard to be sure. Seems promising enough to be worth a mention in this thread, though.

http://radiotalk.galaxyzoo.org/#/subjects/ARG0000orc -- small hourglass morphology, host at Z_sp=0.198

Posted

• by Ptd

Its not an hourglass, but the smallest contour in this one is associated with a spiral in SDDS Image ARG0002j29

Posted

@Ptd--- this is definitely associated with a spiral but it's a more confusing candidate. Thanks 😃

Posted

• by Ptd

Looking straight down onto the disk of this one, so is this what is being asked for? or is this what an ordinary spiral AGN is supposed to look like?

Though calling anything as pretty as that spiral, ordinary, isn't really fair.

Posted

Compact radio emission from a spiral galaxy can be due to either our line-of-sight projection down the axis of the jet or it could be radio emission from star formation. The purpose of this particular subject thread is to specifically find double radio lobes associated with a spiral galaxy. So it's not because the compact sources are not interesting but it's just not the primary focus of the project being discussed in this thread. Please feel free to start another thread focussing on the spiral galaxies with compact radio sources! I am sure many others would be interested in the collection and the topic (myself included) 😃

Does this help?

Posted

• Possible

Posted

• For the ~100 'fair' and 'poor' SDRAGN candidates in my database*, with ~0.035 < z < ~0.32 I've now created similar pairs of images.

In the posts which follow this one, I'll present pairs for objects where I think it's at least somewhat ambiguous whether there's nuclear radio emission. I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale ("definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing)^. If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

In an ideal world, I'd be able to plug these into a Zooniverse-like engine, add some tutorial material, and once it went live, zooites would be able to classify to their hearts' content! Back in GZ forum days, I ran something similar, via the PM system; it was clumsy, inefficient, and error-prone, but I can't think of an alternative ... there are now too many objects to reliably work through on my own (I can't control my biases, or even reliably estimate them! 😦), and ... If you have potentially feasible solutions, let's hear them! 😃

First, through, three unambiguous examples (I hope they're unambiguous!)

The image(s) in this post was (were) created from sources, and using methods, described in this RGZ Talk post. The object(s) at the center(s) of the image(s) is (are) {X}.

*well, not all of them, but as of ~six weeks' ago

^If you think a 4- or 5-point scale is feasible, go for it!

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 2nfj

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J105743.81+151740.3.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 1d8l

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J143554.21+360853.0.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: i1ym

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J115259.71+332531.1.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 2086

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J162037.18+252051.9.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 28nb

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J142305.86+215735.5.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 3pjj

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J110845.48+020240.8.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 38ga

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J141439.50+080450.0.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 2kvu

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J113129.12+162336.3.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 3jjg

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J212804.10+041738.4.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 2gbx

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J120312.94+182322.0.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 18d0

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J164652.71+383845.3.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 3mtv

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J234513.69+030508.8.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 1c36

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J084640.78+364159.5.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 1yui

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J093853.70+255859.6.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 0uce

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J132821.46+453045.1.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 29si

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J121431.51+212540.6.

Posted

• I'd like feedback from AMPAP (as many people as possible), preferrably on a 3-point scale: "definitely nuclear radio emission", "uncertain/don't know/can't decide/etc", "definitely no nuclear radio emission", that sort of thing (if you think a 4- or 5-point scale is feasible, go for it!). If you feel interested enough, I'd also like a similar rating for "radio emission in the form of jet or jets, from the object at the center of the image".

Any way that's convenient for you; e.g. responding to each post individually; or collecting them into a single post (as ivywong did), using an identifier (I've added a unique 4-character IDs to each); sending me a PM or email (if you'd prefer to classify anonymously); ...

Shorthand ID for this image/galaxy: 0giy

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the centers of the images is SDSS J090320.45+523336.1.

Posted

• Perhaps worth a look

SDSS J110151.89+164038.6 - 1237668495777464544

Posted

• thanks to c_cld

Posted

• by ivywong scientist, admin in response to JeanTate's comment.

164.4326, 15.2945: possible confusion

218.9759, 36.1481: uncertain due to offset

178.2488, 33.4253: ok candidate

245.155, 25.3478: ok candidate

215.7744, 21.9599: uncertain

167.1895, 2.0447: uncertain, possible confusion

213.6646, 8.0806: uncertain but good follow-up candidate

172.8713, 16.3934: complicated

322.0171, 4.2940: complicated

180.8039, 18.3895: uncertain

251.7197, 38.6459: possible background source

356.3071, 3.0858: ok candidate

131.67, 36.7: uncertain

144.7238, 25.9832: possible

202.0894, 45.5125: uncertain, possible background source

183.6313, 21.4280: uncertain due to offset

135.8352, 52.5601: ok candidate

Does this help? I didn't think that it'd be useful for me to click "respond" to each image so I've collated all of them in one reply.

Posted

• Thank you very much, ivywong! 😃

Does this help? I didn't think that it'd be useful for me to click "respond" to each image so I've collated all of them in one reply.

Yes, it's easier for me to collect your classifications if they're all in one post. And to help with that, I've added a "shorthand ID", a unique 4-character string (shorthand coordinates - as you've done - works too). And I've edited the main/intro post accordingly too.

Posted

• @JeanTate these are my ratings for your AMAP sample, with short comments

164.4326 15.2945 SDSS J105743.81+151740.3 -- definitely core emission 10/10 no lobes 0/10, adjacent galaxy has core emission

218.9759 36.1481 SDSS J143554.21+360853.0 -- core 0/10 lobes 5/10, adjacent faint red galaxy might be host?

178.2488 33.4253 SDSS J115259.71+332531.1 -- core 10/10 lobes 10/10, seems good candidate to me

245.1550 25.3478 SDSS J162037.18+252051.9 -- core 10/10 (suspect right hand core), lobes 10/10

215.7744 21.9599 SDSS J142305.86+215735.5 -- core 5/10 lobes 10/10, insufficient resolution to separate core and lobes

167.1895 2.0447 SDSS J110845.48+020240.8 -- core 10/10 lobes 0/10, adjacent (background) object has compact emission

213.6646 8.0806 SDSS J141439.50+080450.0 -- core 4/10 (alignment not great but faint, so maybe) lobes 10/10

172.8713 16.3934 SDSS J113129.12+162336.3 -- core 10/10 lobes 10/10 (more tail than lobes), not sure if this host is disk-like though

322.0171 4.2940 SDSS J212804.10+041738.4 -- core 3/10 lobes 3/10, hard to pin down all the sources but alignment with this particular galaxy is not good, the SE bright galaxy is better-aligned, bright galaxy at N of this group also maybe a radio source producing lobes to its 10 o'clock and 4 o'clock

180.8039 18.3895 SDSS J120312.94+182322.0 -- core 10/10 lobes 10/10, host is very faint so no idea of morphology, jets appear angled with the 'nearer' lobe brighter than the 'further' lobe to its NE (not that unusual but explains why source is not exactly in between the two lobes)

251.7197 38.6459 SDSS J164652.71+383845.3 -- core 0/10 lobes 0/10, to me it seems clear that the host is the very faint adjacent galaxy to the SW directly between the two lobes

356.3071 3.0858 SDSS J234513.69+030508.8 -- core 2/10 lobes 10/10, good candidate but unconvinced of disk nature

131.6700 36.7000 SDSS J084640.78+364159.5 -- core 6/10 lobes 4/10, alignment suggests might also be a background source but could even be two compact sources: if it really is a host to core emission then it is still not certain it has lobes but the rating would go up to nearer 8/10.

144.7238 25.9832 SDSS J093853.70+255859.6 -- core 9/10 (alignment very good but weak signal) lobes 10/10, uncertain if it is disk-like but not ruling it out

202.0894 45.5125 SDSS J132821.46+453045.1 -- core 3/10 lobes 5/10, alignment not great but not impossible

183.6313 21.4280 SDSS J121431.51+212540.6 -- core 1/10 lobes 10/10, unconvinced of disk nature, though

135.8352 52.5601 SDSS J090320.45+523336.1 -- core 0/10 lobes 10/10, unconvinced of disk nature, also

Posted

• @Ptd, Dolorous Edd, WizardHowl, C_cld: thanks for you various candidate SDRAGN nominations. 😃

I've added them all to my database, and will process them in the next batch.

Posted

• Thank you very much, WizardHowl! 😄

Posted

• by c_cld

215.74940, 19.59353 SDSS J142259.85+193536.7 3C 300

FIRST cutout

SDSS with FIRST contours

Seems 1237667735058317567 correlated with second radio source 215.74968, 19.59777 1237667782847365185 with close photo z?

or overlap coincidence by chance?

Posted

• by mini.mintaka scientist

Hi Jean,

below are my classifications. I think it's hard to say 'definitely nuclear emission' as many of the candidates require deeper/higher resolution data to confirm anything.

keep up the awesome work 😃

2nfj uncertain/confused?
1d8l uncertain/not aligned
i1ym nuclear or chance alignment
2086 slight offset/merger?
28nb not aligned
3pjj nuclear and/or confused
38ga slight offset
2kvu no idea. weird emission or chance alignment?
3jjg uncertain
2gbx slight offset/uncertain
18d0 offset
3mtv uncertain
1c36 uncertain
1yui slight offset
puce slight offset/many optical sources
28si offset
0giy uncertain/no clear peak/needs better radio resolution!

Posted

• Thank you Minnie! And thanks to Chris Molloy too. 😃

Making some - surely rather arbitrary - assumptions, and adding my 'votes', I've ranked the 17 on how strongly we felt, collectively, that there is nuclear radio emission (from the galaxy in the center of the image) ... they'll appear in the next post.

Posted

• There are five pair-ties, and one three-way tie; ties appear on the same line*. The horizontal lines indicate a gap in the ratings; the first one is big, the second not so much.

What do you think? Any object you feel is badly mis-ranked?

<- unanimity; there is radio emission from the nucleus

< 3-way >

^3-way^^3-way^

<- near unanimity; the radio emission is not from the disk galaxy's nucleus

*except for the three-way tie

The images in this post were created from sources, and using methods, described in this RGZ Talk post. The objects at the center of the images are {X}.

Posted

• Here's another ranking that you may find interesting: the seven objects for which our classifications were most varied. Starting with two objects with strikingly bimodal classifications. Again, ties (or near ties) on the same line, and a horizontal line indicating a gap.

Posted

• by JeanTate

In ARG000109u, z_sp 0.181 SDSS J074714.62+424520.3 might be a boring elliptical, but looks to me more like a (nearly) face-on disk galaxy whose arms are just visible. Radio-wise it's an asymmetric triple. I'll create an overlay soon, and post it. Done.

The image in this post was created from sources, and using methods, described in this RGZ Talk post. The object at the center of the image is SDSS J074714.62+424520.3.

Posted

• another candidate, this time fairly 'nearby': SDSS J142557.05+392444.8 Z_sp=0.143

http://radiotalk.galaxyzoo.org/#/subjects/ARG00016vv -- hourglass with some core emission, host morphology suggestive of interaction, though this also makes it harder to be sure whether it is a disk or not

Posted

• by nico775 translator

Posted

• For this candidate only NVSS seems to show emission potentially beyond the host galaxies whilst FIRST only resolves the core emission. Hard to say whether the diffuse emission seen by NVSS is shocked gas or the result of jets. The top-left host is SDSS J160732.65+531448.8 at Z_sp=0.107 and seems disk-like but GZ1 classed it as uncertain.

Posted

• by ivywong scientist, admin in response to JeanTate's comment.

@JeanTate: this is a tough call without follow-up optical observations. While the central bulge is quite obvious, the arms are somewhat more difficult to confirm with the current image.

Posted

• by ivywong scientist, admin in response to nico775's comment.

Hi @nico775: This too is a tough subject to verify in terms of whether the 2 radio lobes belong to the spiral in the middle. On the other hand, it's clearly a spiral in the middle...

Posted

• Maybe

Posted

• J104632.22+543559.6 - 1237657770176217239

Posted

• SDSS J161358.61+301809.4 - 1237662337330381091

Posted

• ARG000273h - SDRAGN candidate?

Posted

• Same as ARG0001pl7. See thread ARG0001pl7 - is SDSS J161358.61+301809.4 the host? for discussion

Posted

• In ARG0000cyo, z_sp 0.145 SDSS J104632.22+543559.6 doesn't look much like a disk galaxy, but it's certainly the host of a #triple, with very faded lobes:

The image in this post was created from sources, and using methods, described in this RGZ Talk post. The object at the center of the image is SDSS J104632.22+543559.6.

Posted

• Among other things, a consistent count of the number of observed SDRAGNs still seems to elude us ...

Posted

• A quick status update: I have, in my database, 208 candidate SDRAGNs that I have rated at least 'poor', and another 45 I have yet to rate. I am ~eight weeks' behind in checking 'Recent Object Comments'. There are 50 candidates I have rated either 'excellent' or 'good'.

Posted

• by nico775 translator

Posted

• by ivywong scientist, admin in response to JeanTate's comment.

Hi @JeanTate,
Just out of curiousity, when you recently posted a set of SDRAGN candidates, were these candidates from your "good" sample or were they your "ambiguous" sample? I had the impression (and perhaps the wrong one) that the majority of the candidates are somewhat iffy. Does @mini_mintaka know about the 50 good/excellent candidates?

Just curious. Thanks @JeanTate again.
cheers,
Ivy

Posted

• Hi Ivy,

... when you recently posted a set of SDRAGN candidates, were these candidates from your "good" sample or were they your "ambiguous" sample?

In this thread I posted 17 objects. These are a subset of the 101 in the Test thread (the title of which I can edit) thread (pp3 and 4). In turn, these are a subset of the 158 objects I had rated either "fair" or "poor" at the time (~mid-October, 2014).

I had the impression (and perhaps the wrong one) that the majority of the candidates are somewhat iffy.

Your impression is correct; they are* all "somewhat iffy".

Does @mini_mintaka know about the 50 good/excellent candidates?

No. Or at least, not all of them. The 'best' compilation of such candidates is ~five months' old now, and contains only a dozen or so of them; see the What are our VERY BEST 'hourglass sources associated with spirals'? and FIRST contours overlaid on SDSS images - our VERY BEST 'doublelobe spirals' threads. It's important to keep in mind, however, that my ratings of ~five months' ago, the ones I made ~two months' ago, and what I plan to be doing in the next month or so will not be 100% consistent; in particular, I have/will change the ratings of particular candidates. That said, I hope there will be only a handful which move between 'excellent/good' and 'fair/poor' (and none between 'excellent/good' and 'not'!).

Hope this helps.

*or at least were; I haven't yet re-rated any of them, but when I do I expect some will end up as "not", and perhaps one or two "good". There will almost certainly be some which move from "fair" to "poor", and vice versa.

Posted

• I don't think so.

Yes, that's an interesting object! 😃 But is it a disk galaxy which is the host of extended radio emission (whether a lobe, or lobes, or not)? Check out the ARG0000k1z - how many hosts? what kinds of radio emission? thread, and join the discussion!

Please keep possible disk galaxies which are hosts of extended (or just intense) radio emission coming, nico775! 😄

Posted

• SDSS J101704.05+081744.9 - 1237658492268183812

Posted

• Another possible double-hosting disk, http://radiotalk.galaxyzoo.org/#/subjects/ARG0002mxi

In this case, although the double host has no spectroscopic redshift, its photometric redshift (Z_ph~0.113-0.115) is an excellent match to the spectroscopic redshift of the compact radio host galaxy in the same field of view. This suggests the possibility that the activity of both of these galaxies may have been triggered by a recent interaction.

The would-be disk galaxy hosting the double radio source is not imaged quite clearly enough to be sure that it really is a disk but it is certainly an extended object in the SDSS DR12 image. There is a hint of irregularity, as might be expected from a recent interaction, but such an interaction makes it harder to tell if it was a disk galaxy before the interaction, even if its shape is extended now.

Posted

• by ivywong scientist, admin in response to JeanTate's comment.

Thanks heaps @JeanTate. Yes, that is helpful.

Posted

@Dolorous Edd & @WizardHowl: Thanks for your suggestions. These are good lenticular candidates.

Posted

• by JeanTate

ARG00036h0 may contain two SDRAGN candidates. Overlays coming up ...

Posted

• Just for the record

Maybe SBc with little hourglass

SDSS J132809.31+571023.3 - 1237661388138610742

Posted

• by Ptd

The lower left Radio source is close to SDSS J141840.04+430521.9 , however I'm not sure that's not just a convenient random line up.

Posted

• by JeanTate

ARG0002426, host is z_sp 0.118 SDSS J155343.59+234825.4:

Posted

• In ARG0002426:

The image in this post was created from sources, and using methods, described in this RGZ Talk post. The object at the center of the image is SDSS J155343.59+234825.4.

Posted

• by JeanTate

Candidate: the near edge-on spiral near the N edge of ARG0002htb NGC 6045 (as noted by C_cld). It may be 'just' two regions of star formation, but the symmetry with the nucleus is striking!

Posted

• by ivywong scientist, admin in response to JeanTate's comment.

Hi Jean, for this source I am pretty sure that it's mainly star formation. The star forming regions in edge-on spirals do usually look fairly symmetrical about the centre due to projection effects.... sorry 😦.

Posted

• Thanks Ivy. Yeah, I agree that star-formation is more likely.

Somewhat unrelated: is the (1.4GHz) radio emission (which is predominantly synchrotron, right?) from star-forming regions mainly/mostly from supernova remnants? What other sources might there be, the 'double lobes' (bi-polar emission) associated with YSOs (young stellar objects) perhaps?

Posted

Hi Jean,

Typically, we attribute much of the observed radio emission from star formation to SN-driven synchrotron.

But there is a contribution from thermal free-free/bremstrahlung processes coming from HII regions (regions with hot gas ionised by the very massive and very young stars).

Here is a good review by Jim Condon in 1992: http://ned.ipac.caltech.edu/level5/Condon/condon_contents.html

Posted

• Hi Jean !

ARG0002426 has a very pronounced bulge and weird shell-like structures around it doesn't it! weird! the 'shell' structure might be a sign of some recent turbulent activity?? I took a quick look on NED and dont see too many sources with redshift info around it (there are like 2 sources within a few hundred kpc??) ... it'd be interesting to find out how old the radio lobes are...

also, NGC6145 is beautiful 😃 to add to your discussion with Ivy, I find it really interesting to consider how to disentangle radio emission due to SF from emission due to AGN... at cm-wavelengths both are dominated by synchrotron so have similar spectra...

clear skies

minnie

Posted

• by JeanTate

Thanks Ivy and Minnie.

Condon's review is from 1992; has anything much changed, re 'star-forming region' sources of (1.4GHz) radio emission? And has any radio emission been identified in non-star-forming galaxies (other than in/from the AGN)? Not counting Ia supernovae 😉

Posted

• by JeanTate

In ARG0001eba, the radio emission with the odd morphology seems to have z_ph 0.383 ± 0.0456 SDSS J141636.27+353756.8 as host. It's not a boring elliptical:

Overlay image later

Posted

Ellipticals are not boring. They have led very interesting lives 😉

Posted

• by JeanTate

ARG0001n46 Host is z_sp 0.045 SDSS J135217.88+312646.4/UGC 08782. Strong nuclear radio emission, and a #onesided pair of lobes. The host is a late-stage merger, and the spiral arms of one galaxy are still clearly visible:

Posted

• by JeanTate

I'm going to post some material on what I think a systematic search for SDRAGN candidates might involve, and some results from some such searches I've undertaken so far. Over a series of posts. And only in this RGZ thread.

Important to note: there are surely hundreds of possible, good, systematic search classes; I'm going to describe just one (OK, possibly two).

Sketch:

• sample is edge-on/highly inclined disk galaxies
• in SDSS, DR12
• redshift from ~0.08 to ~0.4
• perhaps also only stellar mass > 10^x sols (lots of puts and takes on this)
• search for associated radio emission L1.4GHz > 10^23 W/Hz (say)
• using GZ morphological classifications, constrain the edge-on fraction (of spirals)
• using Meert+ (2014), independently check the GZ morphologies

Depending on numbers, such a search would end up with the space density of SDRAGN candidates (however defined) as a function of redshift (and, perhaps, mass, Hubble Type). The approach hinges on edge-on disk galaxies being able to be robustly selected from SDSS photometric data; yes, there will be false positives - e.g. certain mergers/overlaps - but that's where using low-z GZ morphologies will help.

Some rambling:

• The one great advantage of looking for DLs associated with Eos (edge-on spirals) is that no one can dispute that the host galaxy is a spiral (disk)! Well, almost always, and while my selection criteria do occasionally pick out non-Eos, they're very easy to see. Also, if the universe has no preferred alignment of galaxy disks - with respect to our vantagepoint - then Eos will be an unbiased sample of disk galaxies. On top of that, instead of ~500k SDSS objects to check, there'll likely be only a few 10s of k

• However, what I've discovered so far - with an incredibly small sample - is that radio emission from Eos is ... complicated. For example, I have one example (I think) of a corejet, with the jet extending well beyond the optical boundary (no, it's not an SDRAGN, but then there are also essentially zero/one (Mortganti+) examples of such radio morphology associated with spirals, right?). And quite a few with strong optical AGN signatures (including obvious broadline regions) but zero radio emission; contrary-wise, several with obvious (nuclear?) radio emission and no optical signature of either starformation/starbursts or AGN (nor even of quenched starformation). Perhaps we don't really understand radio emission from disk galaxies very well after all?

• The thing is, for every one of the known SGRAGNs ("Minnie", "Bagchi", Speca, BillKeel's SDRAGN), all at z < 0.14, all but one z < 0.083, there must be dozens detectable out to z ~0.3 (say), given the radio luminosity and assuming we do not live in a special part of the universe (and that evolution is not so rapid as to make z < ~0.1 really special). And in all four cases the optical+radio morphology is totally unambiguous. So where are they all?

• Whether you can 'see' spiral arms or not is affected by a lot of things; an Eos is pretty unambiguous (once you eyeball those selected, you can quickly tell which are not purely disk+bulge galaxies). For example, the arms in the disk of a flocculent spiral become invisible even at quite low z (~0.04?), unless the spiral is nearly face-on and enormous (in physical space). Also, even the arms in grand design spirals can't be 'seen', in SDSS images, much beyond ~0.15 (again, unless huge, in physical space). Ginormous spirals with loose arms, and viewed face on, can be 'seen' out to 0.3-0.35 (I know; I've looked very carefully). However, Eos are quite easy to spot, even out to ~0.4 (true, they have to be physically big).

• Why z >~0.08? Closer than that you have to search a huge chunk of the sky, to be sure you haven't missed any lobes that have already been found in some SDRAGNs (e.g. "Bagchi")

• Yes, some Eos will be lenticulars (arm-less disk galaxies, often with very prominent bulges), but they're still disk galaxies

• jets, plumes, single lobes ... any significantly extended radio emission, not just DLs, will be of interest

Posted

• by JeanTate

After a small trial - only ~300 SDSS 'Eos targets' - I extracted my first real sample, using CasJobs; N=1953. Of these, 201 'only FIRST matches' were found (i.e. FIRST sources within my search radius, no NVSS sources); 100 'only NVSS matches'; and 284 'both FIRST and NVSS matches'. On the SDSS side, 395 are of spectral class QSO and/or subclass AGN and/or BROADLINE and/or STARBURST and/or STARFORMING ("QABSBF"). I spent some time seeing if, using the SDSS data, I could easily impose a quality cut (e.g. one 'Eos' is actually an artifact, associated with the diffspike of a nearby very bright star!), but the number which failed was too small to worry about. A bigger concern - which took me a while to find a robust workaround - was identifying SDSS objects which are not in the FIRST footprint; of course, they will still be in the NVSS footprint.

Cuts etc done, I'm left with 777 targets for which I can expect to be able to create SDSS images, with both FIRST and NVSS contour overlays("FN"); and 56 with just NVSS ("N") (I'm ignoring SDSS 'Eos' with no FIRST/NVSS matches AND not QABSBF; for now at least). I'm now into batch mode, and have finished the first subset, of 78 FN. As expected, there are ~10% which will need redoing or at least checking (my automated method for obtaining FIRST FITS is not always reliable; some FIRST fields are dominated by noise; those are the two main reasons). There's one that's very likely an SDRAGN, and ~ten that need a closer look; this is consistent with the small trial results (115 targets selected, ~ten worth a closer look; no good SDRAGN candidates though).

Posted

• by JeanTate

I did a quick comparison, selecting SDSS DR12 objects by 'Galaxy Zoo, spiral' vs 'Eos', for a small subset (0.23 < z_sp < 0.25, plus some filters for quality and galaxy size).

The 'GZ spiral' selection criterion is 'spiral=1' in the zooSpec table, "flag for combined spiral - 1 if debiased spiral fraction > 0.8, 0 otherwise"; 128 objects. The 'Eos' criterion is 'expAB_r < 0.4', "Exponential fit b/a" (i.e. the axis ratio of the fitted ellipse, using the exponential ('disk') radial profile); 722 objects. All six objects in the former, which also meet the 'Eos' criterion, are in the latter (a good sanity check).

Of course, there are many puts and takes ... for example, not all the 'Eos' are, in fact, disk galaxies (some are undoubtedly overlaps or mergers, for example); I used DR12, but Galaxy Zoo used DR7 (there will surely be more objects, with spectra, in DR12 than DR7); the redshift range is at the very edge of GZ (the debiassing was done only on objects with spectra, and z <= 0.25); I used GZ1 (although GZ2 is not as 'deep'); and so on. However, the main take-away remains: using GZ1 for selection unnecessarily reduces the number of potential candidates.

So, are there any SDRAGN candidates among these 722? Stay tuned!

Posted

• by JeanTate

Candidate: SDSS J115234.35+273636.0 in ARG0001va2:

Posted

• by zutopian

NEW PAPER:

Discovery of rare double-lobe radio galaxies hosted in spiral galaxies

Double-lobe radio galaxies in the local Universe have traditionally been found to be hosted in elliptical or lenticular galaxies. We report the discovery of four spiral-host double-lobe radio galaxies (J0836+0532, J1159+5820, J1352+3126 and J1649+2635) that are discovered by cross-matching a large sample of 187005 spiral galaxies from SDSS DR7 to the full catalogues of FIRST and NVSS. J0836+0532 is reported for the first time.

Authors: Veeresh Singh, C. H. Ishwara-Chandra, Jonathan Sievers, Yogesh Wadadekar, Matt Hilton, Alexandre Beelen
(Submitted on 4 Sep 2015)
http://arxiv.org/abs/1509.01559

PS: I am going to start a discussion in "Journal Club"! EDIT: Here is the link: http://radiotalk.galaxyzoo.org/#/boards/BRG0000009/discussions/DRG0000ctm

Posted

• Thanks zutopian! 😃

I wonder how many of these four had been found by RGZ zooites?

Posted

• At least one

Posted

• Another one had been found, namely:

UPDATE: JT found out the Radio Zoo image ID of another one.: http://radiotalk.galaxyzoo.org/#/subjects/ARG0003frv
She described, how she found out in following discussion.: http://radiotalk.galaxyzoo.org/#/boards/BRG0000003/discussions/DRG0000cud

Posted

• by zutopian

J1649+26: A Grand-Design Spiral with a Large Double-Lobed Radio Source- Mao et al.

The resulting catalogue contained three sources that were identified as spiral galaxies in the “superclean” sample from Galaxy Zoo, and had extended radio emission with ...One was a chance-alignment and another was a nearby star-forming galaxy. The third galaxy, SDSS J164924.01+263502.5 (henceforth J1649+2635), hosts a powerful, double-lobed radio source and is the subject of this paper!

http://arxiv.org/abs/1410.8520

I would like to know the SDSS Object-IDs of the chance-alignment and the star-forming galaxy!
Maybe they are among of thoses, which were posted as candidates in this topic! EDIT: Or might be posted in the future in this topic!

Posted

• by zutopian

UPDATE: Overlay image available now in the discussion!

Posted

• by mini.mintaka scientist

Hi All!

I apologise for the long silence... I was traveling last week 😦

I'm pretty excited about the Singh et al. (2015) paper - it's fantastic that so many people are excited about spiral DRAGNs 😃

Firstly, Dolorous Edd, I am very certain that J1352+3126 is not a spiral DRAGN... this is a well-known early-type galaxy with a disk (see e.g. Morganti et al. 2005)... similar to something like Centaurus A... This source is also known as 3C293 and is a very bright (and famous 😃) radio galaxy ! Ryan Duffin (who found J1649+2635) actually "found" 3C293 as well during his search for Spiral DRAGNs, but a quick literature search was enough to convince him that this was not a spiral !!

As for the other 2 sources... I don't think they are in the Galaxy Zoo "super clean" sample, which is what we used in our search for spiral DRAGNs... I am a bit miffed as to why J0836+0532 wasn't there... I'm still trying to figure that out!

I'm a little bit confused as to why Singh et al. say their paper is "the first systematic attempt" to search for spiral DRAGNs... We present in Mao et al. our "systematic search" ... and certainly you awesome RGZ-ites are searching systematically for these things !!

Sorry this is turning into a long-ish post ...

clear skies

minnie

ps. I keep meaning to ask, would it be useful to have a "live" discussion at some point so we can have a more rapid-fire discussion? as you've probably noticed I'm kind of terrible at posting here regularly... and then i come and write a big ol' essay 😛

Posted

• Most likely a merger, but hey it is not worse than anything in this thread

SDSS J172107.89+262432.1

Posted

• ps. I keep meaning to ask, would it be useful to have a "live" discussion at some point so we can have a more rapid-fire discussion?

IMHO, yes, very much so! 😃 But how to organize such a thing?

Posted

• We could organise a time to meet here on the 'talk' boards... I'll start a new board and see what a good time is for people?

Posted

• by mini.mintaka scientist

I've started a talk board here... Please let me know a good time and I look forward to our 'live' discussion!

Posted

• by zutopian

candidate found by csunjoto:

Outside of SDSS footprint!

Posted

• by zutopian

Authors: Sugata Kaviraj, Stanislav S. Shabala, Adam T. Deller, Enno Middelberg
(Submitted on 17 Dec 2014)
http://arxiv.org/abs/1412.5602

I started a discussion about the paper in the "Journal Club" today. Here is the link.:

Posted

• by JeanTate

ARG00020zx/SDSS J113231.69+250352.7, an Eos?

Posted

• Yes a good candidate

SDSS DR9/ FIRST

Yellow circles are AllWISE sources, Green circles are SDSS DR9 photometric objects

Posted

• by zutopian

Artifact? If not: Associated with spiral?

Posted

• Yes, I think they are FIRST artifacts; here's how the field appears in NVSS:

And, same size, in FIRST:

Posted

They could be artefacts but on the other hand, FIRST is a deeper survey than NVSS...

Posted

• ARG0003ohn

The host is probably Sb0 type galaxy

SDSS J001627.47+022602.1 - 1237678597018550383

Posted

• FIRST contour overlay:

The image in this post was created from sources, and using methods, described in this RGZ Talk post. The object at the center of the image is SDSS J113231.69+250352.7

The contour overlay image in this post was created from sources, and using methods, described in this RGZ Talk thread.

Posted

• by JeanTate

No ARG field, that I know of, and more like a radio-loud core (with a one-sided jet?), than a doublelobe ... z_sp 0.198 SDSS J142820.09+303146.2:

The image in this post was created from sources, and using methods, described in this RGZ Talk post. The object at the center of the image is SDSS J142820.09+303146.2

Posted

• by JeanTate

In ARG00000gj, zph 0.123 ± 0.036 SDSS J120603.08+635731.4 is very likely a disk galaxy, per fracDeV_g (0.18) and fracDeV_r (0):

Contour overlay on order ... ETA: scratch that; here it is:

The image in this post was created from sources, and using methods, described in this RGZ Talk post. The object at the center of the image is SDSS J120603.08+635731.4

Posted

• by JeanTate

In ARG0001b8t, SDSS J083334.29+370945.0 may be an SDRAGN:

The image in this post was created from sources, and using methods, described in this RGZ Talk post. The object at the center of the image is SDSS J083334.29+370945.0

Posted

• by JeanTate

Perhaps a late-stage merger, rather than a pure disk host: ARG0003oz4, SDSS J140231.58+021546.3:

Posted

• by ivywong scientist, admin in response to JeanTate's comment.

Just my 2-cents but I think the offset makes it look like a chance coincidence with a background source, so there is a possibility that it's not related to disk galaxy.

Posted

• by JeanTate

zph 0.244±0.114 SDSS J091558.36+124601.7 is the host of radio emission in ARG0002trz:

The host may not look like a disk galaxy, and may indeed turn out to not be; however, while fracDeV_g is 0.73, fracDeV_r is only 0.016, meaning that whatever morphology it has, it very likely isn't elliptical.

The contour overlay image in this post was created from sources, and using methods, described in this RGZ Talk thread.

Posted

• by JeanTate

zsp 0.093 SDSS J110007.48+104304.0, in ARG00030mv, has an AGN (see spectrum). While it doesn't have double lobes, it's very radio-bright (though with z < 0.1, perhaps not so bright, absolutely). It's definitely not an elliptical:

The contour overlay image in this post was created from sources, and using methods, described in this RGZ Talk thread.

Posted

• Contour overlay image:

The contour overlay image in this post was created from sources, and using methods, described in this RGZ Talk thread.

Posted

• by zutopian

Related paper, which was submitted in 2014.:

New results on the exotic galaxy `Speca' and discovering many more Specas with RAD@home network
Ananda Hota (1, 2), Judith H. Croston (3), Youichi Ohyama (4), C. S. Stalin (5), Martin J. Hardcastle (6), Chiranjib Konar (4), R.P. Aravind (2), Sheena M. Agarwal (2), Sai Arun Dharmik Bhoga (2), Pratik A. Dabhade (2), Amit A. Kamble (2), Pradeepta K. Mohanty (2), Alok Mukherjee (2), Akansha V. Pandey (2), Alakananda Patra (2), Renuka Pechetti (2), Shrishail S. Raut (2), V. Sushma (2), Sravani Vaddi (2), Nishchhal Verma (2)
((1) UM-DAE CBS, India, (2) RAD@home Astronomy Collaboratory, India, (3) U Southampton, UK, (4) ASIAA, Taiwan, (5) IIA, India, (6) U Hertfordshire, UK)

We present the first report on an innovative new project named "RAD@home", a citizen-science research collaboratory built on free web-services like Facebook, Google, Skype, NASA Skyview, NED, TGSS etc.. This is the first of its kind in India, a zero-funded, zero-infrastructure, human-resource network to educate and directly involve in research, hundreds of science-educated under-graduate population of India, irrespective of their official employment and home-location with in the country. Professional international collaborators are involved in follow up observation and publication of the objects discovered by the collaboratory. We present here ten newly found candidate episodic radio galaxies, already proposed to GMRT, and ten more interesting cases which includes, bent-lobe radio galaxies located in new Mpc-scale filaments, likely tracing cosmological cluster accretion from the cosmic web.
Two new Speca-like rare spiral-host large radio galaxies have also been been reported here. Early analyses from our follow up observations with the Subaru and XMM-Newton telescopes have revealed that Speca is likely a new entry to the cluster and is a fast rotating, extremely massive, star forming disk galaxy. Speca-like massive galaxies with giant radio lobes, are possibly remnants of luminous quasars in the early Universe or of first supermassive black holes with in first masssve galaxies. As discoveries of Speca-like galaxies did not require new data from big telescopes, but free archival radio-optical data, these early results demonstrate the discovery potential of RAD@home and how it can help resource-rich professionals, as well as demonstrate a model of academic-growth for resource-poor people in the underdeveloped regions via Internet.

(Submitted on 15 Feb 2014)
http://arxiv.org/abs/1402.3674

The RAD@home project is mentioned in below paper.: 1st and 2nd author are Zooniverse scientists.:

Ideas for Citizen Science in Astronomy
Authors: Philip J. Marshall,1 Chris J. Lintott,2 and Leigh N. Fletcher3
Annual Review of Astronomy and Astrophysics Vol. 53: 247-278 (Volume publication date August 2015)
First published online as a Review in Advance on June 18, 2015
DOI: 10.1146/annurev-astro-081913-035959
http://www.annualreviews.org/doi/full/10.1146/annurev-astro-081913-035959

PS: I copied above text from my today's post in the "Radio Zoo Talk" discussion about Sedna.:

Posted

• by zutopian

In the 1st Radio Zoo paper there is following statement related to this topic.:

Radio Galaxy Zoo: host galaxies and radio morphologies derived from visual inspection
Authors: J.K. Banfield, O.I. Wong, K.W. Willett, R.P. Norris, L. Rudnick, S.S. Shabala, B.D. Simmons, C. Snyder, A. Garon, N. Seymour, E. Middelberg, H. Andernach, C.J. Lintott, K. Jacob, A.D. Kapinska, M.Y. Mao, K.L. Masters, M.J. Jarvis, K. Schawinski, E. Paget, R. Simpson, H.R. Klockner, S. Bamford, T. Burchell, K.E. Chow, G. Cotter, L. Fortson, I. Heywood, T.W. Jones, S. Kaviraj, A.R. Lopez-Sanchez, W.P. Maksym, K. Polsterer, K. Borden, R.P. Hollow, L. Whyte

To date, four examples of spiral galaxies hosting a double-lobed radio source have been discovered (Morganti et al. 2011; Hota et al. 2011; Bagchi et al. 2014; Mao et al. 2015) and Radio Galaxy Zoo has identified several such new candidates. An optical follow-up of these candidates will determine the morphology of these hosts and the relative accuracy of IR colour as a proxy.

(Submitted on 27 Jul 2015)
http://arxiv.org/abs/1507.07272

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• by zutopian

New paper:

The Discovery of a Low-Luminosity SPIRAL DRAGN
Authors: D.D.Mulcahy, M.Y.Mao, I.Mitsuishi, A.M.M. Scaife, A.O.Clarke, Y.Babazaki, H.Kobayashi, R.Suganuma, H.Matsumoto, Y.Tawara

Standard galaxy formation models predict that large-scale double-lobed radio sources, known as DRAGNs, will always be hosted by elliptical galaxies. In spite of this, in recent years a small number of spiral galaxies have also been found to host such sources. These so-called spiral DRAGNs are still extremely rare, with only ∼5 cases being widely accepted. Here we report on the serendipitous discovery of a new spiral DRAGN in data from the Giant Metrewave Radio Telescope (GMRT) at 322 MHz. The host galaxy, MCG+07-47-10, is a face-on late-type Sbc galaxy with distinctive spiral arms and prominent bulge suggesting a high black hole mass.(...)
We suggest that this may indicate the existence of a previously unknown low-luminosity population of spiral DRAGNS.

(Submitted on 15 Sep 2016)
http://arxiv.org/abs/1609.04820

PS: Galaxy image isn't available in SDSS!

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• by zutopian

New paper:

A Search for double-lobed radio emission from Galactic Stars and Spiral Galaxies
Abiel Felipe Ortiz Martínez, Heinz Andernach

We present a systematic search for two types of very unusual astronomical objects:
Galactic stars and spiral galaxies with double radio lobes, i.e. radio emission on opposite sides of the optical object, suggesting the ejection of jets from them. We designed an algorithm to search for pairs of radio sources straddling objects from two unprecedented samples of 878,031 Galactic stars from the Sloan Digital Sky Survey and 675,874 spiral galaxy candidates drawn from the recent literature. We found three new examples of double-lobed radio stars,
while for the spiral galaxies we only rediscovered one known such double source, confirming that the latter objects are extremely rare.

(Submitted on 8 Oct 2016)
https://arxiv.org/abs/1610.02572

PS: H. Andernach is co-author!

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• SDSS J135821.15+032913.3 - 1237655123946504364

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• SDSS J122324.74+070301.9 - 1237661974936944931

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• SDSS J095757.44+315034.3 - 1237664878879113329

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• SDSS J104433.44+284837.3 - 1237667212667846965

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• SDSS J131825.14+094555.9 - 1237662263773298694

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• SDSS J135835.51+550643.5 - 1237661417674703499

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• SDSS J101758.63+040328.3 - 1237654601028468968

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• SDSS J101954.48+393022.8 - 1237661384386740305

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• to the south from https://radiotalk.galaxyzoo.org/#/subjects/ARG0001w1a

A large patch of diffuse emission is visible in NVSS around

SDSS J132259.87+270659.1 - 1237667323799994428

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• Possible SDRAGN candidate ?

SDSS J151534.85+504338.1 - 1237659324948152728

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• SDSS J114958.71+411209.4 - 1237662193450287273

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• by JeanTate

zph 0.350±0.073 SDSS J152825.67+531052.8 (fracDeV <0.5):

but no core emission 😦)

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• SDSS J074714.62+424520.3 - 1237651273492332882

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• SDSS J101550.46+392029.7 - 1237661871319548392

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• SDSS J112306.02+254746.5 - 1237667429032394920

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• SDSS J114047.57+185924.2 - 1237668292838621701

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• SDSS J111726.84+535623.4 - 1237657590319415415

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• by JeanTate

placemarker: all caught up to here

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• SDSS J101559.94+045717.1 - 1237654606396850185

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• SDSS J102254.39+354650.9 - 1237662224594174044

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• SDSS J130615.13+624050.6 - 1237655370901028959

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• SDSS J121135.87+354417.4 - 1237665025978073168

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• SDSS J103930.18+251107.3 - 1237667430101811373

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• SDSS J120058.72+313321.7 - 1237665225693069457

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• SDSS J221203.98+072119.8 - 1237678845038559964

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• SDSS J104502.64+503354.8 - 1237657630059593780

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• SDSS J134702.83+140607.9 - 1237662530062975118

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• SDSS J165620.60+640752.9 - 1237671940340711582

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• by JeanTate

Thanks sisifolibre; noted.

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• SDSS J114626.56+133002.2 - 1237661951324717249

t I think it is overlap of ETG with spiral

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• SDSS J074623.32+251115.6 - 1237657628967240309

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• https://radiotalk.galaxyzoo.org/#/subjects/ARG0001fgz double host QSO? disk? blue elliptical? phz=0.152

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• by JeanTate

Very belatedly, I realized that this thread has not been updated with the Hubble observations of SDRAGNs! 😮

The Radio Galaxy ZooGems Talk thread, which I update whenever a new target is observed, is The Hubble's observations of our targets (updated with each new one). This includes Green DRAGNs, though none of those have been observed, so far (11 September, 2018).

The Who discovered ... ? thread there has lists of the Zooniverse volunteers (RGZ, GZ, and more) who I found as the "discoverers" of each of our targets; there's a good chance at least some entries are incomplete and/or inaccurate.

Finally, the Radio GalaxyZooGems Previously Observed by the Hubble thread has details of targets which the Hubble observed before Program 15445.

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• by JeanTate

SDSS J091949.07+135910.7 is the first SDRAGN candidate that the Hubble observed, in Program 15445 (a.k.a. the Zoo Gems gap-filler), on 15 May, 2018. It is Radio Galaxy ZooGems Subject 18224710:

First noted by antikodon, on Xmas Eve, 2014 ARG0002qvp (S lobe), and WizardHowl on Xmas Day, 2014 in the Discussion thread bright headtail (N lobe).

It's a strange-looking galaxy:

But it's unclear if it's the host of the double lobes (VLASS contours overlaid on a composite Hubble+SDSS canvass):

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• by JeanTate

SDSS J141558.81+132023.7, a.k.a. PKS1413+135, a.k.a. Subject 18239957, is not part of Program 15445, but was observed by the Hubble, back in 1998:

It's obviously an edge-on spiral, but does not have double lobes, at least in FIRST. 😦 A very radio-loud Seyfert perhaps?

(I'll update this post later, when I have a nicer Hubble image)

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• by JeanTate

SDSS J145753.81+283218.7, a.k.a. B2+1455+28, a.k.a. Subject 18274432, was observed by the Hubble in 1999. First noted by mitch, in the old Galaxy Zoo Forum, on 2 July, 2009, and here in RGZ Talk by WizardHowl on 4 April, 2014 ARG0001t9x (SW lobe).

It's clearly a FIRST double lobe source with a (faint) radio core:

And an edge-on spiral galaxy, with a prominent dust lane:

F555W: F814W:

I'll post better Hubble images later, when I get a chance to clean them up.

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• by JeanTate

SDSS J094124.02+394441.8, a.k.a. 3C 223.1, a.k.a. Subject 18224718 is from HAndernach's private collection. It's a weird FIRST radio source, and definitely an inclined spiral. It was observed by the Hubble in 1994, 1995, and 1999:

F555W:

I'll post better Hubble-based images later.

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• by JeanTate

SDSS J120058.72+313321.7, a.k.a. 3C 268.2, a.k.a. Subject 18234879 was observed by the Hubble in 1995 and 1996. Dolorous_Edd first noted it, on 4 September, 2017 in ARG0001mvf

It seems to be an edge-on spiral, and very likely the host of the FIRST radio emission:

F702W:

I'll post better Hubble images later.

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• by JeanTate

SDSS J021958.73+015548.7, a.k.a. UGC 1797, a.k.a. Subject 18220902, first noted by LankyYankee, in the old Galaxy Zoo Forum, on 18 April 2011, and here in RGZ by sisfolibre ARG0003pv9 on 26 November 2016, was always a fave, very likely to be an SDRAGN. The Hubble Program 15445 observation on 3 July, 2018, confirmed it.

FIRST in red, VLASS in yellow; note that this is a PRELIMINARY overlay, and is misaligned by ~0.12".

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• by JeanTate

SDSS J16562058+6407529, a.k.a. Subject 18823886, comes from I. Vasquez Baez & HAndernach personal collection (2012). The Hubble observed it on 24 August, 2018, and confirmed it as an inclined spiral. I'm still working on a contour overlay, so not yet certain if it's got a radio core, though it very likely is an SDRAGN:

I'll be posting more Hubble-based images later.

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• Thank you very much for this update. Subject 18823886 from I. Vasquez Baez & HAndernach always make me think how many candidates with this appearance I must have pass like elliptical... 😦

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• by zutopian

New candidate:

Could you please check and comment overthere?

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• by zutopian

Another new candidate:

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• From @JeanTate

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• by zutopian

I informed about two papers, which were submitted to arxiv some months ago, in following "Journal Club" discussion.:

Statements taken from those papers:

These detections reveal the presumption that NLS1 galaxies labelled radio quiet or radio silent and hosted by spiral galaxies are unable to launch jets to be incorrect.

(...)

Of these, J151020.06+ 554722.0 is a spiral galaxy and J123220.11+495721.8 possibly a spiral. J152205.41+393441.3 is an interacting system of two galaxies in which the NLS1 source is a spiral galaxy and the companion an unidentified, non-active galaxy;

https://arxiv.org/abs/1806.02058

PS: These galaxies are available in SDSS.

Our results suggest that spiral galaxies with pseudo-bulges are able to launch and maintain powerful jets.

https://arxiv.org/abs/1807.02970

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• This is wonderful zutopian, thank you very much! 😃 😃

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• You are welcome!

You might want to check, if these galaxies will be observed by the HST (gap filler projects). I don't mean GZ/ RGZ GEMS.
Another gap filler project's targets are AGNs, as far as I remember.

Or maybe the authors did a HST proposal.

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• SDSS J145237.43+492345.2 - 1237659120935895103

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• by zutopian

New paper:

Rare finding of a 100 kpc large double-lobed radio galaxy hosted in the Narrow Line Seyfert 1 galaxy SDSS J103024.95+551622.7
Suvendu Rakshit, C. S. Stalin, Ananda Hota, Chiranjib Konar
https://arxiv.org/abs/1811.02147

Statement taken from the paper:

Thus, this new object reported here SDSS J103024.95+551622.7, and hosted in a spiral galaxy may represent an oppor- tunity to investigate non-standard modes of relativistic jet production in passively evolving galaxies with smaller black holes masses which may have been more common in the early Universe, prior to the rise of merger-remnant ellipticals and supermassive black holes.

According to the paper the redshift is z=0.435. Here is the link to SDSS.:

http://skyserver.sdss.org/dr14/en/tools/explore/Summary.aspx?id=1237657222559039537

PS: I also informed about this paper in the "Journal Club" by starting a discussion. There is a post, where the corresponding RGZ IDs are given.

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• emission is visible in NVSS ( and TGSS) to the S

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