Galaxy And Mass Assembly (GAMA): Environment-dependent galaxy stellar mass functions in the low-redshift Universe

Abstract

From a carefully selected sample of $52089$ galaxies and $10429$ groups, we investigate the variation of the low-redshift galaxy stellar mass function (GSMF) in the equatorial Galaxy And Mass Assembly (GAMA) dataset as a function of four different environmental properties. We find that: (i) The GSMF is not strongly affected by distance to the nearest filament but rather by group membership. (ii) More massive halos tend to host more massive galaxies and exhibit a steeper decline with stellar mass in the number of intermediate-mass galaxies. This result is robust against the choice of dynamical and luminosity-based group halo mass estimates. (iii) The GSMF of group galaxies does not depend on the position within a filament, but for groups outside of filaments, the characteristic mass of the GSMF is lower. Finally, our global GSMF is well described by a double Schechter function with the following parameters: $\log [M^{\star }/(M_{\odot }{h}_{70}^{-2})]=10.76\pm 0.01$, ${\Phi }_1^{\star }=(3.75\pm 0.09)\times 10^{-3}$ Mpc${}^{-3}$ $h_{70}^3$, ${\alpha }_1=-0.86\pm 0.03$, ${\Phi }_2^{\star }=(0.13\pm 0.05)\times 10^{-3}$ Mpc${}^{-3}$ $h_{70}^3$, and ${\alpha }_2=-1.71\pm 0.06$. This result is consistent with previous GAMA studies in terms of $M^{\star }$, although we find lower values for both ${\alpha }_1$ and ${\alpha }_2$.

20 pages, 10 tables and 19 figures, accepted for publication in Astronomy & Astrophysics (A&A)