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

¹ Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
² Cluster of Excellence Quantum Universe, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
³ International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, Crawley, WA 6009, Australia
⁴ Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122, Australia

^⋆ Corresponding author; antonio.sbaffoni@uni-hamburg.de

Received: 20 December 2024
Accepted: 13 February 2025

Abstract

From a carefully selected sample of 52 089 galaxies and 10 429 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_⋆/(M_⊙h₇₀⁻²)] = 10.76 ± 0.01, Φ₁^⋆ = (3.75 ± 0.09)×10⁻³ Mpc⁻³ h₇₀³, α₁ = −0.86 ± 0.03, Φ₂^⋆ = (0.13 ± 0.05)×10⁻³ Mpc⁻³ h₇₀³, and α₂ = −1.71 ± 0.06. This result is consistent with previous GAMA studies in terms of M^⋆, although we find lower values for both α₁ and α₂.