Large Diffuse source
Is this a single source or several different ones co-incidentally aligned? The sources at top right and below centre both look quite diffuse. There looks to be only one IR-bright source and I can't get either z or extent so can't estimate its size. Anyone able to help?
by ivywong scientist, admin
by HAndernach scientist, translator
Looks definitely like a single source in FIRST, and with an unusual way
of a "restarted" morphology. Due SE the first knot is the brighter,
followed by a diffuse lobe, while this is more or less opposite
on the NW side. There seems to be a radio core of ~1.3 mJy, FIRST
J171840.455+515336.86 which is listed as extended by ~5.8"@145deg in
the FIRST catalog, which is quite close to the major source axis, so it
could be the bases of a single or even twin jet from the core.
Unfortunately the region is out of the SDSS footprint, but checking in
VizieR (http://vizier.u-strasbg.fr/viz-bin) I found a galaxy PGC 2402142
(see http://leda.univ-lyon1.fr/ledacat.cgi?PGC 2402142&ob=ra)
which is quite bright (R~17 B~18.9 mag) and extended (>10") which is clearly the
host galaxy, and coincides with GALEXASC J171840.86+515334.8, There is another
galaxy at J171838.01+515403.6 which in NED is GALEXASC J171838.04+515402.5, or
also 2MASS J17183794+5154033 (i.e. a 2MASS point source, but clearly extended
on the Digitized Sky Survey). Unfortunately NED doesn't have the corresponding
optical galaxy names, although they were published in 2000A&AS..146...19P
Unfortunately the galaxies are not even in the 2MASX catalog, for which
photometric redshifts were recently published (2014ApJS..210....9B).
However, given its extent and apparently brightness, I don't think
it would have a redshift higher than ~0.25, and with a total size of only
2.3' it would not exceed much more than 0.5 Mpc.
By the way, the source (though not its optical ID) was already mentioned in
2011ApJS..194...31Proctor's paper on source groups in FIRST