Physical properties distribution of galaxy population in Abell 2142 cluster

Abstract

In this work, we investigate the physical properties of galaxies in Abell 2142 using photometric and spectroscopic data from the Sloan Digital Sky Survey (SDSS). The sample was selected by two criteria: redshift of 0.0781 ⩽ z ⩽ 0.1038 and the location within a radius of 100 arcminutes from the cluster centre. We found that the sample distributes into 2 groups, a foreground filament galaxies with z ⩽ 0.085 and the cluster members with z > 0.085. The relation between apparent magnitude in g filter band and u – z colour suggests that we can use the u – z equals 3.2 as a criterion to separate galaxies into blue (u – z ⩽ 3.2) and red (u – z > 3.2) sequence galaxies. Moreover, blue sequence galaxies have higher value of equivalent width of hydrogen alpha corresponding to higher star forming activity than red sequence galaxies. The nearby filament contains higher fraction of star forming galaxies (65%) than the cluster Abell 2142 galaxy members (46%). This could be due to difference of the environmental effect.