Constraints on the Evolution of the Galaxy Stellar Mass Function I: Role of Star Formation, Mergers and Stellar Stripping

E. Contini, X. Kang, A. D. Romeo, Q. Xia

Published 2016-04-25Version 1

We study the connection between the observed star formation rate-stellar mass (SFR-$M_*$) relation and the evolution of the stellar mass function (SMF) by means of a Subhalo Abundance Matching technique coupled to merger trees extracted from a N-body simulation. Our approach, which considers both galaxy mergers and stellar stripping, is to force the model to match the observed SMF at redshift $z>2$, and let it evolve down to the present time according to the observed (SFR-$M_*$) relation. In this study, we use two different sets of SMFs and two SFR-$M_*$ relations: a simple power law redshift-dependent and a relation with a mass-dependent slope and redshift-dependent. Our analysis shows that the evolution of the SMF is more consistent with a SFR-$M_*$ relation redshift-dependent and with a mass-dependent slope, in agreement with predictions from other models of galaxy evolution and recent observations. In order to fully describe the evolution of the SMF, both mergers and stellar stripping must be considered, and we find that both have almost equal effects on the evolution of SMF at the massive end. The high-mass end of the SMF obtained by considering stellar stripping is in good agreement with recent observational data from the Sloan Digital Sky Survey (SDSS). At $\log M_* < 11.2$, our prediction at z=0.1 is close to \citet{li-white09} data, but the high-mass end ($\log M_* > 11.2$) is in better agreement with \citet{dsouza15} data which account for more massive galaxies.