Radio-selected Galaxies in Very Rich Clusters at [CLC][ITAL]z[/ITAL][/CLC] ≤ 0.25. II. Radio Properties and Analysis

(Abridged) We report on the properties of radio-selected galaxies within 30very-rich Abell clusters with z < 0.25. These radio data sample the ultra-faint(L(1.4) > 2E22 W/Hz) radio galaxy population with M_R < -21 using thewell-known FIR/radio correlation to link the radio with ongoing star formationwithin individual cluster galaxies. These radio-selected galaxies reveal the`active' galaxy population (starburst and active galactic nuclei) within theserich cluster environments that can be identified regardless of their level ofdust obscuration. For all clusters in our sample, we are sensitive to starformation rates (M > 5 M_sun) > 5 M_sun/yr. We have found that the excessnumber of low-luminosity `starburst' radio-selected galaxies (SBRG) found byOwen et. al. 1999 in Abell 2125 is not indicative of other rich clusters in oursample. The average fraction of SBRG is = 0.022+/-0.003. The A2125fraction is f(SBRG) = 0.09+/-10.03 which is significantly different from thesample average at a >99.99% confidence level. The bimodal structure of both thex-ray brightness distribution and optical adaptively smoothed images of A1278and A2125 suggests that ongoing cluster-cluster mergers may be enhancing thisSBRG population. There is a significant spatial distribution difference betweenthe low and high-luminosity (HLRG) radio-selected populations. The HLRGs seemto be a subclass of the cluster's massive red elliptical population, while theSBRGs have a projected radial distribution more like the blue spiralpopulation. Our results indicate that most of the SBRGs are probably gas-richdisk galaxies undergoing > 5 M_sun/yr of star-formation.Comment: 18 pages, 6 figures, accepted by A