ARG0000id6 - possible gravitational lens
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by Dolorous_Edd
clearly a possible blue arc around
SDSS J133145.32+513431.2 / SDSS J133145.23+513428.8
-- Cluster of Galaxies z_ph ~0.3
part of GMBCG J202.93886+51.57534 Cluster of Galaxies ph_z 0.291650 ( other ID is [SPD2011] 6878 )
Can't ID this one , known one?
Posted
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by Budgieye
Strange, there is no sign of the arc in PanSTARRS, though that survey isn't so good for blue and green.
possible hint of blue, or maybe my imagination.
Posted
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by Dolorous_Edd
There is a hint of arc, it is just obscured by noise
Posted
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by Budgieye
spectral chart in SDSS dr13 for brighter galaxy. Any outliers? There should be an extra peak at about 7000, if the arc was in the sample area.
Galaxy is z=0.2
Green may be due to large amount of star formation and supernovae which is located around the galaxy. Not usual for an elliptical, so that would be interesting.
What is green past that? If the galaxy is acting as a lens, the green must be further away.
Galaxy Redshift Chart https://talk.galaxyzoo.org/#/boards/BGZ0000007/discussions/DGZ0000ulp?page=2
"Green peas" are approximately the same distance. Can't be that.
Spiral galaxy at z=0.3 or 0.4. They look green due to redshift. It might be behind the elliptical, but not actually being lensed.
Quasars at z=4, but they don't form arcs, they remain point-like, although doubled or quadrupled.
Luminous Infrared galaxy at z=4..5. they might form arcs.
spectrum sample on SDSS
http://skyserver.sdss.org/dr13/en/tools/explore/Summary.aspx?id=1237661959368736947
There is no obvious Lyman alpha peak near 7000 . Not sure about that uneven bump.
Green arc might be outside the sample area.
I will call in a lens scientist.
http://skyserver.sdss.org/dr13/en/get/SpecById.ashx?id=7586503345839149056
SDSS J133145.32+513431.2 Brighter galaxy
SDSS dr 13 id for brighter galaxy http://skyserver.sdss.org/dr13/en/tools/explore/Summary.aspx?id=1237661959368736947
SDSS dr 13 id for lower galaxy http://skyserver.sdss.org/dr13/en/tools/explore/Summary.aspx?id=1237661959368736949
SDSS J133145.23+513428.8 lower galaxy
SDSS dr7 id for brighter galaxy http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=588017713120542974
SDSS dr7 id for lower galaxy http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=588017713120542976
Posted
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by ChrisMolloy in response to Dolorous_Edd's comment.
Can lobes be gravitationally lensed? And do you want a contour overlay?
Posted
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by Dolorous_Edd
Yep, will be interesting to have a look, I will make a rudimentary one, but I look forward to HD version )
Edit*
Done
FIRST/SDSS
from the looks of it host is either SDSS J133145.06+513435.9 - 1237661959368736954 or blue arc ?
Posted
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by ChrisMolloy in response to Dolorous_Edd's comment.
Here's the First contour.
The contour overlay image in this post was created from sources, and using methods, described in this RGZ Talk
thread. First in red.If SDSS J133145.06+513435.9 is the host has a DR7 z_ph=0.407 +/-0.084.
Posted
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by JeanTate in response to ChrisMolloy's comment.
Can lobes be gravitationally lensed?
GL is achromatic: light/photons are deflected by exacly the same amount whether they are gamma rays, x-rays, UV, "optical", IR, microwaves, or radio.
Radio GLing of lobes is likely much harder to study because the source (the hot plasma, hotspot, plume, etc) is rarely/barely detectable in any other band (so how do you know it's lensed, esp if you can't see the lens!). Radio emission from a core, on the other hand ...
Posted
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by ChrisMolloy in response to JeanTate's comment.
Thanks. A bit of a needle in a haystack then for this one, as the only real radio reference seems to be an NVSS and ALLWISE citing for SDSS J133145.32+513431.2. The ALLWISE reference is ALLWISE J133145.32+513431.4.
Posted
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by Budgieye
I found one example..
Discovering Distant Radio Galaxies via Gravitational Lensing https://www.cfa.harvard.edu/news/su201608
A Hubble Space Telescope image of distant, bright radio galaxies being
gravitationally lensed by a very large foreground galaxy cluster. The
red contours show the radio emission of these galaxies, which date
from an epoch about three billion years after the big bang. A team of
X-ray astronomers used these lensed radio galaxies to identify and
study distant galaxies with active supermassive black hole nuclei.The astronomers used the Jansky Very Large Array to hunt for lensed
radio sources in this cluster, and detected fifty-one compact galaxies
-- seven whose light seems to be magnified by the cluster by more than factor of two and as much as a factor of nine.Posted
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by Budgieye
Is there any redshift data for the radio emissions?
eg. in the contour lines.
The wavelength of the radio emissions would be redshifted, depending on how far away the source of the radio waves is.
Posted
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by JeanTate in response to Budgieye's comment.
Very cool, thanks Budgieye! 😃
Posted
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by JeanTate in response to Budgieye's comment.
For extragalactic sources, in general, no.
There are 'radio lines', the best known of which is the 21-cm/1.4 GHz HI (atomic hydrogen) line, a hyperfine transition (WP). Most of the radio emission we see here in RGZ is synchrotron emission (WP), where hot electrons spiral around magnetic field lines. While this has a characteristic spectrum (basically "blue", up to the peak, at higher frequencies it fades rapidly), it contains no real redshift information.
The SKA's science goals include a very ambitious one of detecting highly redshifted HI emission, from the "Era of Reionization", though I doubt any future version of RGZ will involve us volunteers trying to identify HI from star-formation (or?) in high-z baby galaxies! 😉
Posted
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by ivywong scientist, admin
At higher GHz frequencies, there is also a thermal component in the observed radio emission from free-free emission.
Posted
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by drphilmarshall in response to Budgieye's comment.
Hi all - the green light looks more like star formation in the group to me, rather than a lensed view of a background object behind the group. But I could be wrong! Not a bad candidate to keep around, maybe try and model.
Given its centroid, I guess the radio emission fits this picture is from a background AGN that is too faint to see in the optical with Sloan. If we did have a lens model, it could tell us where the green source and the radio source were: it's plausible that both the radio source and green star formation are physically associated. It'd be fun if this was a lensed voorwerp 😃
Posted
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by Dolorous_Edd
Thanks for taking a look!
also here is
MzLS+BASS DR4 images
Arc is visible and maybe hint of the blue to 6 o'clock
Posted