The environmental dependence of the stellar mass function at z~1:
  Comparing cluster and field between the GCLASS and UltraVISTA surveys
  We present the stellar mass functions (SMFs) of star-forming and quiescent
galaxies from observations of 10 rich clusters in the Gemini Cluster
Astrophysics Spectroscopic Survey (GCLASS) in the redshift range 0.86<z<1.34.
We compare our results with field measurements at similar redshifts using data
from a Ks-band selected catalogue of the COSMOS/UltraVISTA field. We construct
a Ks-band selected multi-colour catalogue for the clusters in 11 photometric
bands covering u-8um, and estimate photometric redshifts and stellar masses
using SED fitting techniques. To correct for interlopers in our cluster sample,
we use the deep spectroscopic component of GCLASS, which contains spectra for
1282 identified cluster and field galaxies taken with Gemini/GMOS. Both the
photometric and spectroscopic samples are sufficiently deep that we can probe
the SMF down to masses of 10^10 Msun. We distinguish between star-forming and
quiescent galaxies using the rest-frame U-V versus V-J diagram, and find that
the best-fitting Schechter parameters alpha and M* are similar within the
uncertainties for these galaxy types within the different environments.
However, there is a significant difference in the shape and normalisation of
the total SMF between the clusters and the field sample. This difference in the
total SMF is primarily a reflection of the increased fraction of quiescent
galaxies in high-density environments. We apply a simple quenching model that
includes components of mass- and environment-driven quenching, and find that in
this picture 45% of the star-forming galaxies, which normally would be forming
stars in the field, are quenched by the cluster. If galaxies in clusters and
the field quench their star formation via different mechanisms, these processes
have to conspire in such a way that the shapes of the quiescent and
star-forming SMF remain similar in these different environments.
