A Deep Search for Faint Galaxies Associated with Very Low-Redshift C IV
  Absorbers: A Case with Cold-Accretion Characteristics
  Studies of QSO absorber-galaxy connections are often hindered by inadequate
information on whether faint/dwarf galaxies are located near the QSO sight
lines. To investigate the contribution of faint galaxies to QSO absorber
populations, we are conducting a deep galaxy redshift survey near low-z C IV
absorbers. Here we report a blindly-detected C IV absorption system (z(abs) =
0.00348) in the spectrum of PG1148+549 that appears to be associated either
with an edge-on dwarf galaxy with an obvious disk (UGC 6894, z(gal) = 0.00283)
at an impact parameter of rho = 190 kpc or with a very faint dwarf irregular
galaxy at rho = 23 kpc, which is closer to the sightline but has a larger
redshift difference (z(gal) = 0.00107, i.e., dv = 724 km/s). We consider
various gas/galaxy associations, including infall and outflows. Based on
current theoretical models, we conclude that the absorber is most likely
tracing (1) the remnants of an outflow from a previous epoch, a so-called
'ancient outflow', or (2) intergalactic gas accreting onto UGC 6894, 'cold
mode' accretion. The latter scenario is supported by H I synthesis imaging data
that shows the rotation curve of the disk being codirectional with the velocity
offset between UGC 6894 and the absorber, which is located almost directly
along the major axis of the edge-on disk.
