The Radio Luminosity Function and Galaxy Evolution in the Coma Cluster
  We investigate the radio luminosity function (RLF) and radio source
population for two fields within the Coma cluster of galaxies. Our VLA data
reach down to log(L) = 20.23 W/Hz for Coma, and we associate 249 sources with
optical counterparts from the SDSS. Comprehensive optical spectroscopy
identifies 38 of these as members of the Coma cluster, evenly split between AGN
and star-forming galaxies (SFG). The radio-detected SFG are the dominant
population only for ~21 < log(L) < ~22 W/Hz, an interesting result given that
star formation dominates field RLFs for log(L) < ~23. The majority of the
radio-detected SFGs have characteristics of starbursts, including high specific
star formation rates and optical spectra with strong emission lines. In
conjunction with prior studies on post-starburst galaxies within the Coma
cluster, this is consistent with a picture in which late-type galaxies entering
Coma undergo a starburst prior to a rapid cessation of star formation.
Optically bright elliptical galaxies (Mr <= -20.5) make the largest
contribution to the radio luminosity function at both the high (log(L) >~ 22.48
W/Hz) and low (log(L) <~ 21 W/Hz) ends. Through a stacking analysis of these
optically-bright ellipticals we find that they continue to harbor radio sources
down to log(L) = 19.48. However, contrary to published results for the Virgo
cluster we find no evidence for the existence of a population of optically
faint (Mr ~ -14) dwarf ellipticals hosting strong radio AGN.
