Radio Galaxy Zoo Talk

"Live" Spiral DRAGNs chat

  • mini.mintaka by mini.mintaka scientist

    Anyone up for a spiral DRAGNs discussion? (with reference to this talk forum)

    Options:

    1. Wed Sep 23 UTC 0400 (Netherlands 0600, Perth 1200, Los Angeles 2100 on Sep 22)
    2. Wed Sep 23 UTC 2000 (Netherlands 2200, Perth 0400 on Sep 24, Los Angeles 1300)
    3. Fri Sep 25 either of the above times
    4. Mon Sep 28 either of the above times
    5. What works for others?

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    Cool! ๐Ÿ˜ƒ

    Before nominating my preferred times, here they are expressed in 'Sandy territory time' (i.e. East coast of the US, Summer time):

    1. Tue Sep 22nd (today!) midnight
    2. Wed Sep 23rd 16:00 (4pm)
    3. Thu 24th midnight; Fri 25th 4pm
    4. Sun 27th midnight; Mon 28th 4pm

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    Hmm ... am I the only one interested?

    My preference would be any of the "UTC 2000" slots, with Wed 23rd and Fri 25th my preferred days/dates.

    Posted

  • mini.mintaka by mini.mintaka scientist

    Hey Jean ๐Ÿ˜ƒ

    Awesome!

    I'll be here tonight (Sep 23) at UTC 2000... we can talk about spiral DRAGNs, how to find them, how they might have formed, and all sorts of other fun things!

    clear skies

    minnie

    Posted

  • mini.mintaka by mini.mintaka scientist

    Hello!

    Let's talk spiral DRAGNs!

    one of the main motivations for asking the RGZ-ites to look for spiral DRAGNs is to determine just how rare they are...

    Posted

  • JeanTate by JeanTate

    It's 4pm, on Wed 23rd, here in Sandy territory ... hi Minni! ๐Ÿ˜ƒ

    Posted

  • mini.mintaka by mini.mintaka scientist

    Hi Jean ๐Ÿ˜ƒ

    Posted

  • JeanTate by JeanTate

    I've never done this before; how to proceed?

    Posted

  • mini.mintaka by mini.mintaka scientist

    ๐Ÿ˜„

    I'll be online for the next hour or so... I'd like to pick your brain on your thoughts about spiral DRAGNs, and hopefully I can answer some questions that you might have!

    Posted

  • mini.mintaka by mini.mintaka scientist

    Some things that I'd like to discuss are:

    • your thoughts on the Singh et al. (2015) MNRAS paper
    • whether spiral DRAGNs are hard to find or whether they are just REALLY rare
    • possible formation mechanisms
    • more about your edge-on galaxy search method!

    Posted

  • JeanTate by JeanTate

    Sure ... I guess my main question is something like this: "How do we go about assessing the 'SDRAGN candidates' which I, and other zooites, have found?"

    IOW, what objective criteria can we apply to them?

    A second question concerns a Morganti+ paper (if memory serves): "Equally rare, as SDRAGNs, are 'spirals' with strong radio sources (L1.4GHz > 10^24, say) that are clearly 'extended' beyond the optical boundary. Shouldn't we be just as assiduous in looking out for these?" An example I recall is a spiral with twin jets from the nucleus, going way beyond the optical boundary ... it's not - obviously - an SDRAGN though ...

    Posted

  • JeanTate by JeanTate

    I'd like to pick your brain on your thoughts about spiral DRAGNs

    Let the picking begin! ๐Ÿ˜„

    Posted

  • mini.mintaka by mini.mintaka scientist

    "How do we go about assessing the 'SDRAGN candidates' which I, and other zooites, have found?"

    that is an excellent question... We have tended to say 'oh does it look like a spiral', but as you point out, that is far from objective!

    This goes back to something you brought up earlier... what exactly is a spiral?

    a 'classic' spiral is something with clearly defined spiral arms and is quite blue in colour due to active star-formation

    however, as you know, most of the published SDRAGN candidates are rather red... are these then not 'true' spirals?

    Another property of spirals is that they tend to have a lot of gas with which to form stars, which may be traced in the radio by observing the 21cm line...

    Should we be looking for spiral hosts that are blue that contain vast amounts of HI?

    Posted

  • mini.mintaka by mini.mintaka scientist

    "A second question concerns a Morganti+ paper (if memory serves): "Equally rare, as SDRAGNs, are 'spirals' with strong radio sources (L1.4GHz > 10^24, say) that are clearly 'extended' beyond the optical boundary. Shouldn't we be just as assiduous in looking out for these?" An example I recall is a spiral with twin jets from the nucleus, going way beyond the optical boundary ... it's not - obviously - an SDRAGN though ..."

    wait, why is it not obviously an SDRAGN? can you link me to the source?? ... a spiral with twin jets going beyond the optical boundary is exactly what i am interested in finding!

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    your thoughts on the Singh et al. (2015) MNRAS paper

    As I think I said somewhere, they used a method to find candidate SDRAGNs that is remarkably similar to one I'd proposed some time ago, and had started doing some work on. At one level, I'm a little, um, upset that I/we could have found those four (and more?) ourselves, several months ago now ...

    So, obviously, I think the method they used is - at a high level - quite robust! ๐Ÿ˜ฎ

    I agree that one of their four is clearly not a classic spiral (it's a ~mid-stage merger), but that opens the key questions of 'why spirals?' and 'what is a spiral?'

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    I'm sorry that you feel a little hard-done ... I was also kind of cranky because the Singh paper specifically states that theirs is the "first systematic attempt to search for spiral-host double-lobe radio galaxies using large area optical and radio surveys" ... and in Mao et al. (2015) we say we start a project "to systematically search for spiral galaxies associated with large-scale radio lobes"...

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    whether spiral DRAGNs are hard to find or whether they are just REALLY rare

    It depends ... yes, they are uncommon (just < 10 known in the universe out to z=0.1) ... BUT those with (faint) detached lobe(s) and no core will be extremely difficult to find (low L1.4GHz, hard to match radio source with potential host), AND it all depends on what a 'spiral' is ...

    The method I describe on p25 of the 'spirals' RGZ Talk thread should go a long way to contraining just how rare they are (within certain L1.4GHz, z, and projected-distance-to-lobes, ... bounds)

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    possible formation mechanisms

    Easy: I have no idea ... other than interactions/mergers ...

    Posted

  • mini.mintaka by mini.mintaka scientist

    but what i guess comes out of this is, as you have stated 'what exactly is a spiral galaxy'...

    one of the reasons Galaxy Zoo was necessary is because 'spiral' is such a subjective classification...

    from an astronomy point of view, the real question we're asking is, what are the circumstances in which a DRAGN can form? If a merger is required, how powerful must it be? Is a merger even really necessary??

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    Here's something I hadn't really thought about ...

    out to what redshift can we convincingly classify something as 'spiral' ?

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    wait, why is it not obviously an SDRAGN?

    Because it does not have 'lobes', or hotspots ... the DR in SDRAGN, as I understood it, refers to "double lobed radio sources". Ray Norris explicitly highlighted this, in the OP of the Hourglass sources associated with spiral galaxies thread: "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)."

    can you link me to the source??

    Sure; it's somewhere in the Hourglass sources associated with spiral galaxies thread; I'll see how quickly I can find it ...

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    ...but if the radio emission is beyond the scale height of the galaxy (and is not due to star-formation) ... then it should be a lobe? excitement ๐Ÿ˜›

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    out to what redshift can we convincingly classify something as 'spiral' ?

    The original GZ answered that, pretty well: it depends ... in SDSS:

    • physically big, face-on, loose, 2-armed spirals are obvious to at least z=0.35 (I know, I found several)
    • ~'MW' spirals, depending on the looseness of their arms, and apparent size, can be fairly well classified to ~0.2 (maybe a bit less; M31 instead of MW)
    • Eos (edge-on spirals) are pretty easy to classify, out to at least 0.4 (I know, I found several) ... the key is how big they are/appear
    • small, flocculent spirals, viewed at a fairly steep angle, are hard to classify, even at 0.1

    Posted

  • JeanTate by JeanTate

    more about your edge-on galaxy search method!

    What would you like to know?

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    I feel like you've explained this to me before and I didn't understand (sorry)

    how do you know it's a spiral if it's edge-on? How do you know it's not a lenticular (like Morganti et al's) or a flat-ish elliptical? I think one of the issues people have had with 0313-192 is that it is so edge-on that not everyone is convinced it's a 'real' spiral...

    Posted

  • JeanTate by JeanTate in response to JeanTate's comment.

    A start: top of p6 in that thread (copy, without quoting):


    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 ... ๐Ÿ˜ฆ

    *"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 ๐Ÿ˜„


    More later ...

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    oh awesome! I didn't know that!

    thank you!

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    thanks! and which one were you referring to that had radio emission extending beyond the scale height of the galaxy?

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    Should we be looking for spiral hosts that are blue that contain vast amounts of HI?

    Or, hosts that are blue? hosts that contain lots of HI? Separate questions!

    The former will lose the edge-on blue galaxies which are seen through dust (they won't seem blue); but will gain all the blue galaxies which cannot be easily classified as 'spiral' (besides, it's incredibly easy to compile a list of 'blue galaxies').

    The latter cannot be easily found, except quite locally, can they?

    Posted

  • jay.b by jay.b

    Hi team, sorry very late had issues getting in. Reading up now

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    Indeed, HI is difficult to detect beyond z~0.1, but HI maps of the sky are pretty complete to z~0.04 i think (HIPASS?)

    (The VLA project CHILES is observing HI down to z~0.4 ... but requires 1000h ...)

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    I'm sorry that you feel a little hard-done ... I was also kind of cranky because the Singh paper specifically states that theirs is the "first systematic attempt to search for spiral-host double-lobe radio galaxies using large area optical and radio surveys"

    Yeah, that must have hurt, big time.

    But then there's Ray ... kicked off that thread then abandoned us, only to return when ATLAS got mentioned ... what are we zooites, clickslaves?

    For myself, the bigger frustration is being told I cannot write a paper (with hopes that it could/would be published) - on SDRAGNs or anything (this is not the first time/project) - unless I team up with professional astronomer ... the real world can be/appear quite cruel at times ...

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    You're right of course about the dust reddening ... but are the spiral arms so affected? The spiral arms contain dust, but I thought they were still predominately blue?

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    Well, the GZ1 (the original GZ) papers do not explicitly say this, but it is possible to make good inferences based on one of the key papers (their cutoff is z=0.25). Some of what I wrote is what I found myself, not yet published (another long story) ...

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    !!! Jean!!! I am positive that I have told you multiple times that anyone can publish good science !!!

    grin also yeah, Ray did do that didn't he... He's very busy but I can talk to him

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    Hi Jay!

    Posted

  • JeanTate by JeanTate in response to jay.b's comment.

    Welcome! ๐Ÿ˜ƒ

    Reading up now

    Looking forward to your questions and inputs! ๐Ÿ˜„

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    hurumph... well those numbers are very useful and should be published!

    Posted

  • mini.mintaka by mini.mintaka scientist

    BTW Jean, wrt your idea to search primarily EoS... it'd be very interesting if we (ever) had enough sources to determine whether extended radio emission was more likely to be seen in edge-on sources...

    I am still confused/awed by the result that the orientation of seyfert jets don't seem to show any relationship with the major/minor axes of the host galaxies...

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    which one were you referring to that had radio emission extending beyond the scale height of the galaxy?

    It's not in that list of papers, rather one ~half-way down p10:


    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
    • Vรฉron-Cetty&Vรฉron 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).


    My memory is not so bad ... it's Morganti+ (2011)!

    The galaxy in Emonts+ (2009) is one I produced a contour overlay for; in the next post I'll copy/paste that post from the 'SDRAGN' thread ...

    Posted

  • jay.b by jay.b

    Ok so obviously a consistent way of identifying spirals is essential...
    how robust are the spiral classifications given in papers like Meert et al. and galaxy zoo?

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    It's ~halfway down p13:


    (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:

    enter image description here

    enter image description here

    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:

    enter image description here

    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

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    ah... that's one of the hosts that is not a spiral?

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    Right, I remember now!! I've worked with Bjorn, he is an awesome collaborator!!

    I think that at the time I had dismissed the host as 'not being spiral'... but indeed (as Bjorn and Raffaela's papers states) disk galaxies that host DRAGNs are also exceedingly rare (and don't really make sense)

    Posted

  • jay.b by jay.b

    also remind me, whats the cutoff for it to be a proper DRAGN jet power wise?

    Posted

  • mini.mintaka by mini.mintaka scientist in response to jay.b's comment.

    ah that's a good question jay ! I don't know if people have 'quantified' the robustness of the classifications? But Jean's search method would have compared the GZ classifications with Meert et al...

    Posted

  • mini.mintaka by mini.mintaka scientist in response to jay.b's comment.

    For Mao et al (2015), Ryan and I chose a cutoff of 10^23W/Hz... this would have excluded most of the star-forming sources, but may miss some lower power DRAGNs...

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    how do you know it's a spiral if it's edge-on?

    You don't ... all you know for sure is that it has a (big) disk ... but then when you look really closely at (many/most) lenticulars (which, by definition, do not have arms), you find that an awful lot do, in fact, have arms (just that they're hard to see, do not contain star-forming regions/dust/etc, ...). One of Ron Buta's 'galaxy morphology' papers is well worth a detailed read on this (and other topics) ... 'visual band'-based morphological classifications contain a great many, um, misleading things ...

    This gets back to "what's a spiral anyway?"

    Posted

  • mini.mintaka by mini.mintaka scientist in response to jay.b's comment.

    Hey, thanks SO much for this "live" chat... I've learned a lot ... I hope you've found it useful too ...

    Unfortunately I have to go...

    Feel free to chat amongst yourselves ๐Ÿ˜›

    Shall we do another one of these again soon? I find I respond a lot better to more 'instant' communication, than message boards ...

    Thank you SO much...

    Posted

  • mini.mintaka by mini.mintaka scientist in response to JeanTate's comment.

    FWIW, i think your search method should/will turn up lots of interesting sources... as we've confirmed again tonight... disk galaxies with DRAGNs are just as interesting/confusing/odd as SDRAGNs...

    Jean, I can't wait to see all your disk-DRAGNs ๐Ÿ˜› DDRAGNs!

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    The spiral arms contain dust, but I thought they were still predominately blue?

    (re Eos): As usual, it depends ... IIRC, if you have good spectra and photometry, you can make good estimates of things like dust absorption and likely ('current') SFR (star formation rate)

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    !!! Jean!!! I am positive that I have told you multiple times that anyone can publish good science !!!

    Indeed.

    And even more times have I been told/advised that I should not even think of trying to do something like that alone/with other ordinary zooites! Within the Zooniverse there's at least one Planet Hunters paper with ordinary zooites are (most of the) authors, inc the lead ... but that team first got several published with PH team members are (lead) authors ... I even researched this, and wrote up what I found in a different forum (CosmoQuest, I have a link if you're interested).

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    One nice thing about 'my' Eos method is that it's quite insensitive to jet/lobe orientation wrt the disk ... so long as the radio source does not appear to be entirely coincident with 'just' the nucleus! (even an extended source, not obviously going beyond the optical boundaries, can be 'found', and if it's luminous enough ...)

    Posted

  • JeanTate by JeanTate in response to jay.b's comment.

    Meert+: there are some 'false positives', but 'visual inspection' can weed out all (that are big/bright enough; at the small/faint end it's nigh on impossible). IIRC, there are few 'false negatives'

    GZ: it depends on where you cut ... superclean? ~zero false positives; clean? some; ... bigger problem is false negatives (significantly inclined 'reddish' spirals with indistinct arms are all-too-easily classified as 'smooth, in between', i.e. ellipticals)

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    That's a good working value ... and if you go out a bit (z-wise), you won't find many lower-luminosity DLs anyway ...

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    You're welcome ... I hope you read what's in this thread after you left, and also ask questions/for clarification of things you realize you didn't quite get (when re-reading).

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    Gotta bail myself too. It's been fun, and I hope useful to not only us three but also other readers ...

    Posted

  • jay.b by jay.b in response to JeanTate's comment.

    I'm only just catching up with the science on this (been mostly involved on the data side) so this was very useful for me too. Hopefully will contribute more in future. Keep plugging away Jean, don't let publications and stuff get you down.
    Science for science's sake and all that ๐Ÿ˜‰

    Posted

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

    HIPASS was a 3-pi sky survey of HI and was completed more than a decade ago so I think that its sensitivity limit is around the z~0.03 mark as the source counts do drop off quite dramatically. ALFALFA has published its40% catalogue but it's not a complete catalogue nor is it a complete survey. For the next generation of deep all-sky HI emission, you'll all have to wait for the pre-SKA experiments to get up and running. WALLABY will do the 3-pi sky from the south and there will be a Northern counterpart being planned for the new Apertif instrument currently being deployed on the Westerbork array.

    Posted

  • JeanTate by JeanTate in response to JeanTate's comment.

    I even researched this, and wrote up what I found in a different forum (CosmoQuest, I have a link if you're interested).

    It's a thread called Why is there essentially zero work being done by Citizen Scientists (amateurs)?

    Posted

  • raynorris by raynorris scientist in response to mini.mintaka's comment.

    Sorry I didnt see the earlier posts. I'm good for any time today!

    Posted

  • JeanTate by JeanTate in response to raynorris's comment.

    Hi Ray, very happy to see you dropping by! ๐Ÿ˜ƒ

    If you're still around, or any time later today (US East Coast time), I'll be here most of the time, so at least you and I could chat.

    Also, if you have a chance, would you mind reading/skimming the Hourglass sources associated with spiral galaxies thread (which you kicked off), and commenting on some of the most promising SDRAGN candidates?

    Posted

  • mini.mintaka by mini.mintaka scientist

    Hi Ray and Jean ๐Ÿ˜ƒ

    Jean, it may be more efficient for you to choose a few of your most promising SDRAGN candidates and repost them here? Is this a good place to start? http://radiotalk.galaxyzoo.org/#/boards/BRG0000003/discussions/DRG00007g8

    Posted

  • raynorris by raynorris scientist in response to mini.mintaka's comment.

    Hi Jean

    Good to talk to you again. Yes I'm sorry for my absence - I tend to get involved in a large number of projects so only have a limited time available for each. And when I see one happily moving along with good people driving it, then I reckon I'm probably superfluous!

    I just had a look at the link you gave and saw you have lots of interesting sources, but (a) I don't really have enough time to go through them all in detail, and (b) I don't think I have any special expertise in picking out the best ones - I think you and Minnie are probably far more expert than me to do that. But if you could pull a few of the ebst ones together, as Minnie suggests, then we could discuss them in detail.

    Cheers

    Ray

    Posted

  • raynorris by raynorris scientist in response to mini.mintaka's comment.

    BTW I'm currently on sabbatical at the University of Cape Town, South Africa, so I'm on the same time-zone as Minnie in The Netherlands. So at least we only have to worry about 2 timezones, not 3, for an on-line chat!

    Posted

  • JeanTate by JeanTate in response to mini.mintaka's comment.

    A bit late catching up; yes, the FIRST contours overlaid on SDSS images - our VERY BEST 'doublelobe spirals' thread is a good place to start. Note, however, that it's now almost 14 months' old, so there's likely another ~dozen SDRAGN candidates that are ~as good. For example, one that I've not yet gotten around to doing a contour overlay for is SDSS J113231.69+250352.7; here it is, together with Dolorous Edd's Aladin overlay:

    enter image description here

    enter image description here

    Posted

  • JeanTate by JeanTate in response to raynorris's comment.

    Sure thing.

    A suggestion, if I may: ordinary zooites have little to no appreciation for how professional astronomers work; in particular, the typical timeframes for even a 'cool discovery' paper are so long as to trigger incredulity (there are, likely, many reasons for this; a discussion for another time perhaps?).

    Further, 'oldbie' zooites who lived through "Hanny's Voorwerp" and "Green Peas" came to expect (completely unrealistically) that zooites' discoveries which trigger superlatives from professionals - such as "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)" - that something similar would happen if they did, in fact, discover such rare and important objects*.

    So, perhaps some timely feedback? Every month/quarter or so drop by to post a comment? Even better, if you yourself cannot devote the time to at least kicking off the process of writing a paper on the best ~dozen or so candidates already found, perhaps you could provide practical suggestions to ordinary zooites on how they might go about doing so?

    don't think I have any special expertise in picking out the best ones - I think you and Minnie are probably far more expert than me to do that

    Thanks! ๐Ÿ˜ƒ

    One of the key things we - Minnie, me, and others - are stuck on is "just what objective criteria should we use, for selecting 'spiral galaxy host', from among the candidates?" The literature is quite, um, confused on this; depending on exactly how you define 'spiral galaxy host', there are between ~four and ~a dozen SDRAGNs (or spirals-hosting-radio loud-AGNs, or spirals-with-many kpc-long-jets, or ...) in the literature, with ~twice as many 'just as good' among the hundreds of candidates we've found so far.

    *the fuss over Space Warps' "red ring" discovery is a more recent example; counter-examples are many, but so deeply buried as to be all-but-unnoticable

    Posted

  • JeanTate by JeanTate in response to JeanTate's comment.

    In case any reader is curious:

    physically big, face-on, loose, 2-armed spirals are obvious to at least z=0.35 (I know, I found several)

    I "published", as a Zooniverse Letter, a result: Physical Properties of the First Four HUDS

    Eos (edge-on spirals) are pretty easy to classify, out to at least 0.4 (I know, I found several)

    Likewise, Six SDSS 0.30 < z < 0.32 Huds (of the Eos Kind).

    Posted