purple object is on the left outer side of the ring?
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by Budgieye moderator
What is it? 37 references in NED, 47 in SIMBAD Anyone feel like wading through them to see if any actually mention this in detail?
http://skyserver.sdss.org/dr9/en/tools/explore/obj.asp?ra=35.222635321025244&dec=0.5567671665433799 1237663784749695005
SDSS J022054.53+003323.7posted by Rossrr3
#UM 420
SIMBAD say galaxy
notes:
The infrared source IRAS F02183+0019 is not coincident with the galaxy 16 arcsec. West, UGC 1809.SBSG 0218+003 KUG 0218+003 Full data in the catalogue KUG UM 420 Full data in the catalogue UM
IRAS F02183+0019 Full data in the catalogue IRAS SCHG 0218+003 WISE J022054.53+003324.4http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%401395896&Name=IRAS F02183%2B0019&submit=submit
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Here is the SDSS object page and NED
http://skyserver.sdss.org/dr9/en/tools/explore/obj.asp?id=1237663784749695005
Nearly all NED references are about this I think.
I've got a feeling this is a similar object as the Quasar with ears only with better imaging and spectra available.
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by CeciliaB
Excerpt from NED Note 1: UM 420 is a blue compact galaxy, but not a dwarf object, hosting intense starformation activity....we observe a central region and two bright H(alpha) tails pointing towards different directions. Its kinematics is also perturbed. It has a very low metallicity for an object with its absolute optical/NIR luminosities, suggesting that it is a merging of two independent galaxies....Its colors and properties are somewhat contaminated by the spiral disk of the foreground galaxy UGC 1809...
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by bluemagi
https://inspirehep.net/record/833480/files/um420_espectros_um420_paper.png
This is a spectrum of UM420 . Wolf-Rayet Galaxy UM420.
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by Budgieye moderator
Oooh, it looks very hot. Lots of emission peaks. Any redshift with it? (looks about 0.05)
https://inspirehep.net/record/833480/files/um420_espectros_um420_paper.png
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NED UM 420 z=0.058420 +/- 0.000040 nearby UGC 01809 z=0.024370 +/- 0.000090
Information and figures from A VLT VIMOS integral-field spectroscopic study of perturbed blue compact galaxies: UM 420 and UM 462 B. L. James Y. G. Tsamis M. J. Barlow
Excerpts from abstract and introduction
Both galaxies display signs of ongoing perturbation and/or
interaction. UM 420 is resolved for the first time to be a merging
system composed of two starbursting components with an ‘arm-like’
structure associated with the largest component....
Pustilnik et al. (2004) describe UM 420 as being a possible ‘sinking
merger’, i.e. harbouring a satellite galaxy that is sinking into a
larger, gas-rich companion.
Maps of UM 420 (a) and UM 462 (b) in Hα; left-hand column – flux per 0.33 arcsec2 spaxel; centre column – radial velocity (relative to heliocentric systemic velocity of +17 545 and +1057 km s−1 for UM 420 and UM 462, respectively); right-hand column – Hα FWHM corrected for the instrumental point spread function.
UM 420: The distribution of flux per 0.33 × 0.33 arsec2 spaxels of [Oiii]λ5007 (left-hand panel) and [Nii]λ6584 (right-hand panel)
Excerpts from Conclusions
Both systems show signs of interaction and/or perturbation with the
former galaxy currently undergoing a merger..
The spatially resolved emission line maps in the light of [O iii] and
Hα have revealed two main areas of massive star formation in UM 420
along with an ‘arm-like’ structure..
Regarding the abundance of nitrogen, and the N/O ratio, this result is
in qualitative agreement with the finding that these BCGs cannot be
classified as WR galaxies as the characteristic broad-line stellar
features have not been detected by VIMOS; the existence of WR stars in
them is an open issue.(WR = Wolf-Rayet galaxy)
First / Extract Stripe 82 Image Cutout
https://third.ucllnl.org/cgi-bin/stripe82cutout
Visual comparison of this object, 'Quasar with ears' posted by JeanTate in this thread and similar object posted by vrooje in this thread
http://skyserver.sdss.org/dr9/en/tools/explore/obj.asp?id=1237663784749695005
http://skyserver.sdss.org/dr13/en/tools/explore/Summary.aspx?id=1237668504364187727
http://skyserver.sdss.org/dr14/en/tools/explore/Summary.aspx?id=1237661064955101286
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by bluemagi
Its redshift is Z:0.060604 and Distance is 238 (Mpc).
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by Ghost_Sheep_SWR in response to bluemagi's comment.
Source?
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by bluemagi
PDF . arXiv:0909.4735vl [astro-ph.GA] 25 Sep.2009.
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by Ghost_Sheep_SWR in response to bluemagi's comment.
Link?
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by bluemagi
I should say the same study you got your info from. A Vlt.Vimos integrel Field Spectroscopic Study of Perturbed blue compact galaxies Um420&Um462. by B.L.James,G.Tsamis and M.J.Barlow.
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by Ghost_Sheep_SWR in response to bluemagi's comment.
Thanks for the clarification, I assumed NED / SIMBAD take the latest available information for objects. Guess not then, that redshift is indeed probably more accurate although moderately further away.
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So to conclude, my best guesses.
Color of central object is probably a combination of ionized OIII (dark magenta / purple) but only the brightest part, maximum starburst (blue-white but probably whiter than regular starburst) and very likely an AGN (white). Gives pink.
White sidewings not entirely sure why they are pure white, but maximum starburst whiter than regular? Possible this kind of starburst is just very bright in all 3 bands which makes white.
Also some other elements contributing, I guess green. And also overlapping galaxy which will redden UM 420.
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