The importance of the local density in shaping the galaxy stellar mass functions

TL;DR

This study demonstrates that local density significantly influences galaxy stellar mass functions across different environments and redshifts, with its impact varying by mass and environment, highlighting the importance of local processes over global halo effects.

Contribution

It provides a comprehensive analysis of local density effects on galaxy mass functions across multiple surveys and redshifts, emphasizing the dominance of local over global environment influences.

Findings

Local density affects galaxy mass distribution at all redshifts and environments.

In clusters, local density impacts only low-mass galaxies.

Global environment is less influential than local density at $z\,\leq\,0.8$.

Abstract

Exploiting the capabilities of four different surveys --- the Padova-Millennium Galaxy and Group Catalogue (PM2GC), the WIde-field Nearby Galaxy-cluster Survey (WINGS), the IMACS Cluster Building Survey (ICBS) and the ESO Distant Cluster Survey (EDisCS) --- we analyze the galaxy stellar mass distribution as a function of local density in mass-limited samples, in the field and in clusters from low (z>0.04) to high (z<0.8) redshift. We find that at all redshifts and in all environments, local density plays a role in shaping the mass distribution. In the field, it regulates the shape of the mass function at any mass above the mass limits. In clusters, it seems to be important only at low masses (log M_ast/M_sun <10.1 in WINGS and log M_ast/M_sun < 10.4 in EDisCS), otherwise it seems not to influence the mass distribution. Putting together our results with those of Calvi et al. and Vulcani et al. for the global environment, we argue that at least at $z\leq 0.8$ local density is more important than global environment in determining the galaxy stellar mass distribution, suggesting that galaxy properties are not much dependent of halo mass, but do depend on local scale processes.