Evidence for a Rotational Component in the Circumgalactic Medium of
  Nearby Galaxies
  We present results of a study comparing the relative velocity of $\rm
Ly\alpha$ absorbers to the rotation velocity of nearby galaxy disks in the
local universe ($z \leq 0.03$). We have obtained rotation curves via long-slit
spectroscopy of eight galaxies with the Southern African Large Telescope, and
combine this dataset with an additional 16 galaxies with data from the
literature. Each galaxy appears within $3R_{\rm vir}$ of a QSO sightline with
archival Cosmic Origin Spectrograph (COS) spectra. We study the velocity
orientation of absorbers with respect to nearby galaxy's rotation, and compare
with results from both the Steidel et al. (2002) monolithic halo model and a
new cylindrical Navarro-Frenk-White galaxy halo model to interpret these data
in the context of probing 3D galaxy halos via 1D QSO absorption-line
spectroscopy. Relative to these models we find that up to $59\pm5\%$ of $\rm
Ly\alpha$ absorbers have velocities consistent with co-rotation. We find the
$\rm Ly\alpha$ co-rotation fraction to decrease with galaxy luminosity ($L^*$)
and impact parameter in a model-independent fashion. We report that both
anti-rotating absorbers and those found near luminous galaxies ($L \gtrsim 0.5
L^*$) mostly have low Doppler $b$-parameters ($b \lesssim 50$ km $\rm s^{-1}$).
Absorbers consistent with co-rotation show a wide range of Doppler
$b$-parameters. Finally, we find a strong anticorrelation between co-rotation
fraction and galaxy inclination, which is at odds with recent metal-line
kinematic studies and suggests the kinematic and geometric distribution of the
circumgalactic medium is complex and multiphase.
