Radio-selected Galaxies in Very Rich Clusters at z ≤ 0.25. II. Radio Properties and Analysis

摘要: We report on the properties of radio-selected galaxies within 30 very-rich Abell clusters with z . 0.25. The radio, optical, and x-ray data for these were presented in Paper I (Morrison et al. 2002). These radio sample ultra-faint (L1.4 ≥ 2 × 10 22 W Hz −1 ) galaxy population MR ≤ −21 using well-known FIR/radio correlation to link ongoing star formation individual cluster galaxies. Spectroscopic redshifts exist ∼ 96% optical identifications. reveal ‘active’ (starburst active galactic nuclei) rich environments that can be identified regardless their level dust obscuration. new provide largest date low-luminosity allowing an unbiased search dusty starbursting For all our sample, we are sensitive rates (M 5M⊙) & 5 M⊙yr have found excess number ‘starburst’ (SBRG) by Owen (1999) 2125 is not indicative other sample. average fraction SBRG h fSBRG i = 0.022 ± 0.003. A2125 0.09 0.03 which significantly different from at a > 99.99% confidence level. Both A1278 A1689 slightly rest 90% bimodal structure both brightness distribution adaptively smoothed images suggests cluster-cluster mergers may enhancing this population. (and high-luminosity) due interaction ICM. mid-infrared ISOCAM results A1689’s emission low- high-luminosity AGN origin except one galaxy. There significant spatial difference between low (HLRG) populations. core radius 0.40 0.08 Mpc 3× larger than HLRG radius. In addition, 48% SBRGs colors bluer typical Sab compared 4% HLRGs. absolute magnitude SBRG’s −21.93 0.05, while HLRG’s it −22.33 0.07, indicating less optically luminous counterparts. HLRGs seem subclass cluster’s massive red elliptical population, projected radial more like blue spiral Our indicate most probably gas-rich disk undergoing M⊙ yr star-formation. Subject headings: galaxies: evolution — clusters: starburst continuum: