Environmental Dependence of Stellar Mass, Star Formation Rate, Specific Star Formation Rate, and AGN Activity for an Apparent Magnitude Limited Main Galaxy Sample of the SDSS DR7

Abstract

Abstract In this study, we used an apparent magnitude limited Main galaxy sample of the Sloan Digital Sky Survey Data Release 7 (SDSS DR7), and investigated the environmental dependence of stellar mass, the star formation rate (SFR), the specific star formation rate (SSFR, the star formation rate per unit stellar mass) and active galactic nucleus (AGN) activity. To decrease the Malmquist bias, we divided the whole apparent magnitude limited Main galaxy sample into many subsamples with a redshift binning size of $ \Delta{z}$$ =$ 0.01, and analysed the environmental dependence of these properties of subsamples in each redshift bin. It turns out that a strong environmental dependence of the stellar mass, SFR and SSFR could be observed in nearly all redshift bins of the apparent magnitude limited Main galaxy sample, and that in most redshift bins (except for a low redshift region of $ z$$ =$ 0.02 to 0.06), the fraction of AGNs in the sample at low density apparently was larger than that in the sample at high density.