Did any GZ zooites discover unusual radio galaxies?
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by JeanTate
As of just now, there are 262 posts in the GZ forum's Radio source thread, dating from December 09, 2007.
Many posts in that thread report a positional (on the sky) co-location of an SDSS object - usually a galaxy - and a radio source as identified in an online catalog, often NED; quite a few posts do not report the source for the radio object.
The last two posts, by c_cld, have some very nice superposition images, WISE+FIRST+SDSS; for example1:
Is there a reasonably straight-forward way of checking what zooites have posted in that thread?
For example, how to obtain a FIRST image, with the appropriate 'plate scale', and overlay it on the SDSS image of what is obviously a spiral galaxy (to see, for example, if it's an hourglass or doublelobe, or if there's a jet)?
1 c_cld writes "SDSS image under NVSS contours seems offset? can't check the location of the contours but need inspection"
Posted
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by JeanTate in response to JeanTate's comment.
Over in that GZ forum thread, c_cld has already started just such an analysis, and has reported the following:
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"First step: list of objects posted translated in DR10 Ids,ra,dec" (here)
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"Second step: FIRST Catalog Search" (here)
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by JeanTate in response to JeanTate's comment.
And he's reported his first hit, SDSS J085556.36+491110.6, a nice z_sp 0.093 elliptical with a strong double lobe (and a trio of 6C sources, according to NED):
The SDSS object was posted in that thread on June 19, 2009, by Helly, as DR7 ObjId 588009365860450522.
Posted
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by c_cld
😃
Posted
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by c_cld
NGC 5782 , UGC 9602
FIRSTJ145555.4+115151 NVSS J145555+115150
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by c_cld
SDSS J132117.81+423515.2 1237662196142047400 z spec=0.079
3C 285 -- Active Galaxy Nucleus
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by c_cld
SDSS J094443.18+024754.1 1237654599951057142 zspec=0.220
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by c_cld
SDSS J035654.28+001331.4 1237646587163770997
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by c_cld
SDSS J083053.44+191315.8 1237667108501127783
NVSS J083053+191314
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by c_cld
SDSS J095759.32+032725.8 1237654604784205971 zspec=0.165
Posted
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by JeanTate in response to C_cld's comment.
DR10 says SDSS J083053.44+191315.8 is a z_ph ~0.082 galaxy; if it's the host, it would be extremely unusual! 😮 It's very small (PetroRad_r 1.56" ± 0.18), faint (modelmag_r 21.76), and blue (g-i -0.17, though u-r is 2.23). Maybe the host is something else, perhaps a z>~0.8 elliptical invisible in SDSS? Or maybe the z_ph is wildly wrong, and it's actually a QSO?
Posted
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by JeanTate in response to C_cld's comment.
Morphologically, the host seems to me to be a disturbed disk galaxy, likely a merger. It's an AGN, and it clearly has two radio lobes, making it a DRAGN. It would thus seem to meet raynorris (scientist)'s criterion for being a radio-loud spiral. Yet as it's a 3C object, it's surely been investigated to death a long time ago, so what are we missing?
Here's the DR10 image, zoomed in:
Posted
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by JeanTate in response to C_cld's comment.
I think the host of this spectacular #wat is SDSS J035654.28+001331.4, a.k.a. 2MASX J03565430+0013313, which is a z_sp (not SDSS) 0.042 elliptical (possibly a giant, possibly with an AGN):
The second lobe is not clear in FIRST, but seems to be present in NVSS:
Posted
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by c_cld in response to JeanTate's comment.
3C 285
The Interaction between Radio Lobes and Hot Gas in the Nearby Radio Galaxies 3C 285 and 3C 442A
paper related to proposal OPTICAL EMISSION IN DOUBLE RADIO GALAXY LOBES: CYCLE 4, HST Proposal 5156, Philippe Crane, NASA Headquarters
Posted
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by WizardHowl in response to JeanTate's comment.
I wouldn't assume that just because a radio-loud galaxy is in 3C it means we won't learn anything from looking them up in SDSS - there's always the possibility the association between the radio and optical has not been made before. This applies especially to strange radio morphologies as well as galaxies that are very faint in optical. As an example look at 3C 343, which appears in RGZ as http://radiotalk.galaxyzoo.org/#/subjects/ARG00001qs and has an optical host in SDSS: I could not find a spectrum for the host galaxy in NED/SDSS! By all means add the above DRAGN spiral to the list of objects in the thread started by raynorris 😃
Posted
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by c_cld in response to JeanTate's comment.
[quote]
DR10 says SDSS J083053.44+191315.8 is a z_ph ~0.082 galaxy; if it's
the host, it would be extremely unusual! 😮 It's very small
(PetroRad_r 1.56" ± 0.18), faint (modelmag_r 21.76), and blue (g-i
-0.17, though u-r is 2.23). Maybe the host is something else, perhaps a z>~0.8 elliptical invisible in SDSS? Or maybe the z_ph is wildly
wrong, and it's actually a QSO?[\quote]
SDSS J083053.44+191315.8 1237667108501127783
Recorded in multiple catalogs with spectroscopic redshift 2.572
Catalog of radio galaxies with z>0.3 (Khabibullina+ 2009)
Search for megamasers in type-2 AGNs (Bennert+, 2009) 2009ApJ...695..276B
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by zutopian in response to C_cld's comment.
SDSS J132117.81+423515.2 1237662196142047400 z spec=0.079
3C 285 -- Active Galaxy NucleusCorresponding Radio Zoo image:
http://radiotalk.galaxyzoo.org/#/subjects/ARG00010mw
Posted
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by JeanTate
The field ARG0000da3 contains the NE lobe and core; the SW lobe is clearly seen in the FIRST image:
The NVSS image also shows the core+double lobe structure:
The host is very likely the z_sp 0.351 SDSS J103556.67+542612.5:
This image quality isn't great, but to me this looks like a messy merger involving a giant disk galaxy and perhaps another disk galaxy or an ETG (elliptical).
What do you think?
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by JeanTate in response to JeanTate's comment.
Here's that image processed to bring out the features I think I see1
1 I applied a Gaussian blur, then 'posterized' it; I have found that this two-step image processing often makes much clearer what I can make out, with difficulty, in the original. Of course, this is not a rigorously scientific approach (but 'posterizing' does produce something somewhat resembling isophotes)
Posted
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by zutopian
New GZ blog post:
Remarkable Discoveries Underway –
We’ll be highlighting some of these curious discoveries in subsequent blogs, but here’s a recently found one that’s just “too good to be true.”
What is the ID of the Radio Zoo image in Talk ?
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by JeanTate in response to zutopian's comment.
Discussion of it is in the thread, An impossible source
Cool, eh? 😃
Posted
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by zutopian
Copy from an interview with Dr Ivy Wong, 29 May 2014 :
Were you surprised at the level of interest and the amount of contributions you were receiving from the public in helping provide classifications?
(...) By doing so, we made a discovery of a giant Wide-Angled-Tail (WAT) source within a few days of our launch. The maps that we used were published in 1995. Much to the surprise of the science team, this WAT stayed unnoticed until December 2013 when a few of our super citizen scientists reported that the source that they were looking at was actually part of a much larger structure. The discovery paper is being written as we speak!
http://www.icrar.org/multimedia/interviews_with_researchers/dr-ivy-wong
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by JeanTate in response to zutopian's comment.
42jkb (a.k.a. Dr Julie Banfield) wrote a Zooniverse email newsletter on this, back in January (for a copy of that email newsletter, see the 5th post in the Suggestions on how to improve RGZ Talk ... thread here).
Posted
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by JeanTate
Some FIRST and/or NVSS contours overlaid on SDSS images, of objects posted in the Galaxy Zoo forum thread Radio sources.
SDSS J095713.70+410616.4 (source):
SDSS J103935.45+263948.5 (source):
SDSS J103059.09+310255.7
(source):
SDSS J085748.06+004641.3 (source):
SDSS J163352.28+475943.0
(source):
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. Image centers (J2000.0) are the galaxies SDSS J095713.70+410616.4, SDSS J103935.45+263948.5, SDSS J103059.09+310255.7, SDSS J085748.06+004641.3, and SDSS J163352.28+475943.0, respectively; "z_sp" their SDSS spectroscopic redshifts.Posted
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by ivywong scientist, admin
The last merging system is brilliant. What a tail!
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by JeanTate in response to ivywong's comment.
It is pretty cool, isn't it?
Here's a zoomed out view, with both FIRST and NVSS contours overlaid:
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. Image center (J2000.0) is the galaxy SDSS J163352.28+475943.0; "z_sp" its SDSS spectroscopic redshift.Posted
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by JeanTate
From the GZ forum Radio Sources thread, I selected objects zooites posted which look like 'not boring ellipticals'. There are 182. I have finished checking them, to see if any could be SDRAGN candidates.
Apart from SDSS J132318.81+030807.1 - which I wrote up in the ARG0003mpf - SDRAGN! green! voorwerpje (EELR)! wat! Hybrid? thread - I have found none*. 😦
While the 'selection function' for these 182 objects may be fairly easy to describe, attempting to draw robust conclusions re the likely number of SDRAGN candidates in the (DR7) SDSS footprint would not be easy. However, the distribution of redshifts, and the incidence of nuclear radio emission, seem consistent with these broad statements:
- apparently undisturbed spirals/disk galaxies with detectable FIRST nuclear emission are rather weak radio sources (in terms of radio luminosity)
- merging/interacting objects seem more common, as radio sources, than disk galaxies in general
- extended radio emission - jets, plumes, lobes, etc - is rare in either of the above two classes.
In the next few posts I'll present some interesting objects (among the 182).
*so far anyway; there are some 'loose ends' I should look into
Posted
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by 1001G
ARG0001oqk Z 0.255 SDSS J105006.42+304045.5 FIRST J105006.6+304045 RADIO CONTOUR RING GALAXY
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by JeanTate in response to 1001G's comment.
Very cool, 1001G! 😃
In ARG0001oqk:
If one host, is this an extremely unusual #hybrid?
If more than one host, how many? And which are they? And what are the radio morphologies associated with each?
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 J105007.83+304010.8
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by 1001G
ONE MORE GALAXY WITH A RADIO RING CONTOUR? SDSS J103308.47+090214.3 AT Z 0.227? SEE ARG00035r9.
THIS RING SEEMS TO BE FROM 1 GALAXY.Posted