Outskirts of Galaxy Clusters A1139, A1314, A1656, A2040, A 2052, A2107: Star-Formation Rate.
KOPYLOVA F.G. and KOPYLOV A.I.
Abstract (from CDS):
We investigate the variation of the fraction of galaxies with suppressed star formation ( M K < -21 . m 5) and early-type galaxies ( frac E ) of the "red sequence" along the projected radius in six galaxy clusters:Coma (A1656), A1139, and A1314 in the Leo supercluster region ( z∼ 0.036). According to SDSS (DR10) data, frac E is the highest in the central regions of galaxy clusters and it is, on the average, equal o 0.62 ± 0.03, whereas in the 2-3 R/ R_200c interval and beyond the R sp ∼ 0.95 ± 0.04 R_200m radius that we inferred from the observed profile frac E is minimal and equal to 0.25 ± 0.02. This value coincides with the estimate frac E = 0.24 ± 0.01 that we inferred for field galaxies located between the Hercules and Leo superclusters at the same redshifts. We show that the fraction of galaxies with suppressed star formation decreases continuously with cluster radius from 0.87 ± 0.02 in central regions down to 0.43 ± 0.03 in the 2-3 R/ R_200c interval and beyond R sp, but remains, This decrease is especially conspicuous in the galaxy mass interval log M * [ M_solar] = 9.5-10. We found that galaxies with ongoing star formation have average clustercentric distances 1.5-2.5 R/ R_200 c and that their radial-velocity dispersions are higher than those of galaxies with suppressed star formation.
galaxies - clusters-galaxies - evolution-galaxies - star formation