Environmental dependence of the galaxy stellar mass function in the Dark
  Energy Survey Science Verification Data
  Measurements of the galaxy stellar mass function are crucial to understand
the formation of galaxies in the Universe. In a hierarchical clustering
paradigm it is plausible that there is a connection between the properties of
galaxies and their environments. Evidence for environmental trends has been
established in the local Universe. The Dark Energy Survey (DES) provides large
photometric datasets that enable further investigation of the assembly of mass.
In this study we use ~3.2 million galaxies from the (South Pole Telescope)
SPT-East field in the DES science verification (SV) dataset. From grizY
photometry we derive galaxy stellar masses and absolute magnitudes, and
determine the errors on these properties using Monte-Carlo simulations using
the full photometric redshift probability distributions. We compute galaxy
environments using a fixed conical aperture for a range of scales. We construct
galaxy environment probability distribution functions and investigate the
dependence of the environment errors on the aperture parameters. We compute the
environment components of the galaxy stellar mass function for the redshift
range 0.15<z<1.05. For z<0.75 we find that the fraction of massive galaxies is
larger in high density environment than in low density environments. We show
that the low density and high density components converge with increasing
redshift up to z~1.0 where the shapes of the mass function components are
indistinguishable. Our study shows how high density structures build up around
massive galaxies through cosmic time.
