The Environment of Massive Quiescent Compact Galaxies at $0.1<z<0.4$ in
  the COSMOS Field
  We use Hectospec mounted on the 6.5-meter MMT to carry out a redshift survey
of red ($r-i>0.2$, $g-r>0.8$, $r<21.3$) galaxies in the COSMOS field to measure
the environments of massive compact quiescent galaxies at intermediate
redshift. The $>90\%$ complete magnitude limited survey includes redshifts for
1766 red galaxies with $r < 20.8$ covering the central square degree of the
field; $65\%$ of the redshifts in this sample are new. We select a complete
magnitude limited quiescent sample based on the rest-frame $UVJ$ colors. When
the density distribution is sampled on a scale of 2 Mpc massive compact
galaxies inhabit systematically denser regions than the parent quiescent galaxy
population. Non-compact quiescent galaxies with the same stellar masses as
their compact counterparts populate a similar distribution of environments.
Thus the massive nature of quiescent compacts accounts for the environment
dependence and appears fundamental to their history.
