Halo Mass Dependence of HI and OVI Absorption: Evidence for Differential
  Kinematics
  We studied a sample of 14 galaxies (0.1 < z < 0.7) using HST/WFPC2 imaging
and high-resolution HST/COS or HST/STIS quasar spectroscopy of Lya, Lyb,
OVI1031, and OVI1037 absorption. The galaxies, having 10.8 < log(M/M_solar) <
12.2, lie within D = 300 kpc of quasar sightlines, probing out to D/R_vir = 3.
When the full range of galaxy virial masses and D/R_vir of the sample are
examined, 40% of the HI absorbing clouds can be inferred to be escaping their
host halo. The fraction of bound clouds decreases as D/R_vir increases such
that the escaping fraction is around 15% for D/R_vir < 1, around 45% for 1 <
D/R_vir < 2, and around 90% for 2 < D/R_vir < 3. Adopting the median mass
log(M/M_solar) = 11.5 to divide the sample into "higher" and "lower" mass
galaxies, we find mass dependency for the hot CGM kinematics. To our survey
limits, OVI absorption is found in only 40% of the HI clouds in and around
lower mass halos as compared to 85% around higher mass halos. For D/R < 1,
lower mass halos have an escape fraction of 65%, whereas higher mass halos have
an escape fraction of 5%. For 1 < D/R_vir < 2, the escape fractions are 55% and
35% for lower mass and higher mass halos, respectively. For 2 < D/R_vir < 3,
the escape fraction for lower mass halos is around 90%. We show that it is
highly likely that the absorbing clouds reside within 4 virial radii of their
host galaxies and that the kinematics are dominated by outflows. Our finding of
"differential kinematics" is consistent with the scenario of "differential wind
recycling" proposed by Oppenheimer et al. We discuss the implications for
galaxy evolution, the stellar to halo mass function, and the mass metallicity
relationship of galaxies.
