Halo Gas and Galaxy Disk Kinematics of a Volume-Limited Sample of MgII
  Absorption-Selected Galaxies at z~0.1
  We have directly compared MgII halo gas kinematics to the rotation velocities
derived from emission/absorption lines of the associated host galaxies. Our
0.096<z<0.148 volume-limited sample comprises 13 ~L* galaxies, with impact
parameters of 12-90 kpc from background quasars sight-lines, associated with 11
MgII absorption systems with MgII equivalent widths 0.3< W_r(2796)<2.3A. For
only 5/13 galaxies, the absorption resides to one side of the galaxy systemic
velocity and trends to align with one side of the galaxy rotation curve. The
remainder have absorption that spans both sides of the galaxy systemic
velocity. These results differ from those at z~0.5, where 74% of the galaxies
have absorption residing to one side of the galaxy systemic velocity. For all
the z~0.1 systems, simple extended disk-like rotation models fail to reproduce
the full MgII velocity spread, implying other dynamical processes contribute to
the MgII kinematics. In fact 55% of the galaxies are "counter-rotating" with
respect to the bulk of the MgII absorption. These MgII host-galaxies are
isolated, have low star formation rates (SFRs) in their central regions (<1
Msun/yr), and SFRs per unit area well below those measured for galaxies with
strong winds. The galaxy NaID (stellar+ISM) and MgIb (stellar) absorption line
ratios are consistent with a predominately stellar origin, implying
kinematically quiescent interstellar media. These facts suggest that the
kinematics of the MgII absorption halos for our sample of galaxies are not
influenced by galaxy--galaxy environmental effects, nor by winds intrinsic to
the host galaxies. For these low redshift galaxies, we favor a scenario in
which infalling gas accretion provides a gas reservoir for low-to-moderate star
formation rates and disk/halo processes.
