The Massive End of the Stellar Mass Function

TL;DR

This study refines the galaxy stellar mass function at z=0.1 by applying flux corrections to SDSS data, revealing a shallower slope at the massive end and significantly altering the estimated stellar mass density.

Contribution

It introduces a method to correct galaxy flux measurements using stacking, impacting the derived stellar mass function and its comparison with previous estimates.

Findings

Flux corrections range from 0.05 to 0.32 mag for massive galaxies.

The corrected stellar mass function slope is shallower than Li & White (2009).

The stellar mass density for massive galaxies is 3.36 times larger than Li & White (2009).

Abstract

We derive average flux corrections to the \texttt{Model} magnitudes of the Sloan Digital Sky Survey (SDSS) galaxies by stacking together mosaics of similar galaxies in bins of stellar mass and concentration. Extra flux is detected in the outer low surface brightness part of the galaxies, leading to corrections ranging from 0.05 to 0.32 mag for the highest stellar mass galaxies. We apply these corrections to the MPA-JHU (Max-Planck Institute for Astrophysics - John Hopkins University) stellar masses for a complete sample of half a million galaxies from the SDSS survey to derive a corrected galaxy stellar mass function at $z=0.1$ in the stellar mass range $9.5<\log(M_\ast/M_\odot)<12.0$. We find that the flux corrections and the use of the MPA-JHU stellar masses have a significant impact on the massive end of the stellar mass function, making the slope significantly shallower than that estimated by Li \& White (2009), but steeper than derived by Bernardi et al. (2013). This corresponds to a mean comoving stellar mass density of galaxies with stellar masses $\log(M_\ast/M_\odot) \ge 11.0$ that is a factor of 3.36 larger than the estimate by Li \& White (2009), but is 43\% smaller than reported by Bernardi et al. (2013).