ARG00036bv SDSS J233639.03+085005.6 the radio source? SDSS J233640.30+084955.1 a green Galaxy?
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by 1001G
SDSS J233639.03+085005.6 Radio source Galaxy?
SDSS J233640.30+084955.1 Green Galaxy or what is it?
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by Dolorous_Edd
http://radiotalk.galaxyzoo.org/#/subjects/ARG00036bn
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by 42jkb scientist, admin
As per the link above, these appear to be Gren Pea galaxies (http://arxiv.org/abs/0907.4155). Galaxies with extreme star formation. Looking at the WISE images in the link does indeed show a large amount of star formation (band 4) and the colour image is red. However, the emission from band 4 can also indicate heating of dust by the AGN. Separating the emission from star formation from that of hot dust from the AGN is rather difficult and I don't think that there is a solution on how to do this yet.
My question is, if a galaxy shows this much star formation and the AGN appears to be rather large (so an older AGN), which came first the star formation activity or the AGN? This ties into what we are trying to use the RGZ results from. A great find and will pass this on the the Green Pea experts.
Has there been a number of these objects?
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by Dolorous_Edd in response to 42jkb's comment.
What do you think about
Not exactly RGZ but ...
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by 42jkb scientist, admin in response to 42jkb's comment.
I think I would have picked the green galaxy has the host. However, I could be completely wrong on that. Definitely worth looking into where the radio emission is coming from.
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by 42jkb scientist, admin in response to Dolorous Edd's comment.
OK this is getting interesting! From your GZ link, it looks like a few of these do indeed have AGN signatures. There is also mention of a flat radio spectrum, however I'm not sure how they define flat...
A typical radio lobe will have a radio spectral index of -0.7 (radio flux proportional to frequency^(spectral index)).
A steeper radio spectral index (-1.0) sometimes indicates high redshift galaxies.
Spectral index around -0.4 usually indicates the core dominated emission (i.e., not radio lobes)
Something flatter ( 0 to +1) indicates Blazars.I more familiar with objects with a negative spectral index and I would call -0.4 flat whereas others call 0 and higher flat.
Interesting! An object with that extreme star formation and to have an AGN is a type of galaxy in a certain phase of galaxy formation. I wonder what the redshift ranges of these types of galaxies are?
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by Dolorous_Edd
Just want to drop this one here
http://radiotalk.galaxyzoo.org/#/subjects/ARG0002w9m
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by WizardHowl in response to Dolorous Edd's comment.
Here are the most green galaxies I have come across from my non-red collection, although I wouldn't call them green peas.
http://radiotalk.galaxyzoo.org/#/subjects/ARG00012bc -- hourglass, slightly disturbed-looking host, Z_ph~0.2http://radiotalk.galaxyzoo.org/#/subjects/ARG000346x -- small doublelobe, host has elongated shape, Z_ph~0.27-0.29
http://radiotalk.galaxyzoo.org/#/subjects/ARG000087m -- hourglass, disturbed host surrounded by ring, Z_ph~0.31-0.35
In terms of their place in the AGN/starforming debate, these galaxies don't seem to have exceptionally bright cores so perhaps they have younger AGN, if they have AGN at all? It's a shame they don't have spectra...
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by 1001G
There was a 2009 study and paper on Green Pea Galaxies by Carolin N. Cardamone and others.
Cornell UniversityLibrary
arXiv.org > astro-ph > arXiv:0907.4155
Astrophysics > Cosmology and Nongalactic Astrophysics
Galaxy Zoo Green Peas: Discovery of A Class of Compact Extremely Star-Forming Galaxies
Carolin N. Cardamone and others 2009 Paper.Posted
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by 1001G
A RGZ question. Does the Green Pea Galaxy show on the FIRST & NVSS images.
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by JeanTate
Here are a couple of FIRST overlays; the first has a high threshold and fairly tight contours, the second a low threshold and more widely spaced ones (in terms of intensity/flux steps):
Perhaps the host(s) is (are) some other, faint SDSS photometric object(s)?
How do we rule out an "artifact" explanation of the almost uniform green color of SDSS J233640.30+084955.1? If this is truly a Green Pea (GP), it is a very unusual one ... IIRC, GPs are more compact that this, and do not have such prominent nuclei/bulges. Pity we don't have a spectrum ...
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 center of the ARG image ARG00036bv.Posted
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by 42jkb scientist, admin
OK, I am super excited by this discussion and I am going to be taking over on the science for this. I hoping that this turns out to be something really great.
Green pea galaxies shouldn't have radio emission from AGN, they do have radio emission associated with the star formation. http://arxiv.org/abs/1110.3312
I'm interested in the green galaxies (emission line galaxies or "green beans") with the radio emission from an AGN. http://en.wikipedia.org/wiki/Green_bean_galaxy
I will grab the sources you have found and start another thread where we can create a database of them. If you see any more can you tag them #green? Thanks!
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by 42jkb scientist, admin in response to WizardHowl's comment.
I agree, these AGN could be young or even old and may have already turned off. I would like to follow these sources up to see where they stand in the evolutionary phase of galaxies.
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by 42jkb scientist, admin in response to JeanTate's comment.
I have no idea how one would rule out an artifact in the SDSS images. Believe it or not, this is my first time going beyond looking at only IR and radio, so this optical territory is really new to me.
It is true that the host galaxy to the radio is a fainter SDSS galaxy not seen here. Looking at the images you made I would like to say that the host is the green galaxy but that could just be me wanting it to be. I will have to look deeper into this and see what other radio data is available.
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by JeanTate in response to 42jkb's comment.
Cool! 😃
For those hunting by 'apparent color in SDSS images', note that Green Peas (and Beans) are only green in a particular wavelength range ... below x, the [OIII] (etc) emission will be in the SDSS g band, so they'll appear more magenta(ish); above y, [OIII] etc emission will be in the i band, so they'll look ~red ... except that [OII] emission - if strong - will appear in the g band, and they'll appear magenta/purple/pink/(i.e. lots of R and B; little G).
The former should be relatively common; the latter, pretty rare, because whatever y is, at such great distances, Peas will be invisible in SDSS (too faint). Here's an example of a (z < x) 'purple pea' (source):
And how do I know it's a Pea? Because of its spectrum! 😃 Nebular emission dominates (continuum barely detected), it's narrow, and [OIII] > Hα (and [OII]):
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by 42jkb scientist, admin
Here is the link to the new board creating the database for these objects
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by Dolorous_Edd in response to 42jkb's comment.
Speaking about green galaxies with radio emission, this one is known, but still maybe interesting
Last 2 posts in this thread
http://radiotalk.galaxyzoo.org/#/boards/BRG0000003/discussions/DRG00005gp
And
http://radiotalk.galaxyzoo.org/#/boards/BRG0000002/discussions/DRG00007xi
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by JeanTate
Zoomed in contour overlay (green galaxy z_ph 0.357±0.1019/0.359±0.1044):
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 J233640.30+084955.1; "z_ph" its SDSS photometric redshift.Posted
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by Dolorous_Edd
Maybe not related to the topic, but here is sample of galaxies with green regions near nucleus
All of them host compact radio source
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by Dolorous_Edd
I will add this one to this thread, because I didn't see it here
http://radiotalk.galaxyzoo.org/#/subjects/ARG0000css
http://radiotalk.galaxyzoo.org/#/boards/BRG0000002/discussions/DRG00005v2
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by 42jkb scientist, admin in response to Dolorous Edd's comment.
Thanks! Will add this to my list to follow up.
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by Dolorous_Edd
Worth to check
http://radiotalk.galaxyzoo.org/#/subjects/ARG0001vqk
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by 42jkb scientist, admin in response to Dolorous Edd's comment.
Thanks for the newest candidate, I will definitely follow this one up. Also, thank you for posting these and locating them for me. We are in the process of trying to understand what these objects are. One of the interesting things we are noticing in our small sample so far is that they all seem to lie around z = 0.3. Will keep you posted.
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by Dolorous_Edd
Another galaxy with green regions near nucleus
http://radiotalk.galaxyzoo.org/#/boards/BRG0000002/discussions/DRG000087o
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by Dolorous_Edd
Very speculative, but worth to mention anyway
http://radiotalk.galaxyzoo.org/#/subjects/ARG0000z9b
http://radiotalk.galaxyzoo.org/#/subjects/ARG0002qt6
http://radiotalk.galaxyzoo.org/#/subjects/ARG0000qwm
Known QSO but still can possess some interest
http://radiotalk.galaxyzoo.org/#/subjects/ARG000216r
Also recomend to check SDSS J115839.97+153639.5 (dunno is it green enough )
P.S
Maybe I should post next candidates in "Green galaxies associated with RGZ sources" thread?
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