Mass segregation trends in SDSS galaxy groups

TL;DR

This study investigates how galaxy stellar mass varies with distance from the center in SDSS galaxy groups, revealing weak mass segregation influenced by galaxy and halo mass, with implications for dynamical friction efficiency.

Contribution

It provides new observational evidence of mass segregation trends in galaxy groups and analyzes their dependence on galaxy and halo mass using SDSS DR7 data.

Findings

Weak mass segregation observed in SDSS groups

Mass segregation strength decreases with increasing halo mass

Dynamical friction appears inefficient in high-mass haloes

Abstract

It has been shown that galaxy properties depend strongly on their host environment. In order to understand the relevant physical processes driving galaxy evolution it is important to study the observed properties of galaxies in different environments. Mass segregation in bound galaxy structures is an important indicator of evolutionary history and dynamical friction timescales. Using group catalogues derived from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) we investigate mass segregation trends in galaxy groups at low redshift. We investigate average galaxy stellar mass as a function of group-centric radius and find evidence for weak mass segregation in SDSS groups. The magnitude of the mass segregation depends on both galaxy stellar mass limits and group halo mass. We show that the inclusion of low mass galaxies tends to strengthen mass segregation trends, and that the strength of mass segregation tends to decrease with increasing group halo mass. We find the same trends if we use the fraction of massive galaxies as a function of group-centric radius as an alternative probe of mass segregation. The magnitude of mass segregation that we measure, particularly in high-mass haloes, indicates that dynamical friction is not acting efficiently.