Dark Matter and HI in Ultra-Diffuse Galaxy UGC 2162
  Our GMRT HI observations of the ultra diffuse galaxy (UDG) UGC 2162,
projected $\sim$ 300 kpc from the centre of the M77 group, reveal it to a have
an extended HI disk (R$_{HI}$/R$_{25}$ $\sim$ 3.3) with a moderate rotational
velocity (V$_{rot} \sim$ 31 km/s). This V$_{rot}$ is in line with that of dwarf
galaxies with similar HI mass. We estimate an M$_{dyn}$ of $\sim$ 1.14 $\times$
10$^{9}$ M$_\odot$ within the galaxy's R$_{HI}$ $\sim$ 5.2 kpc. Additionally,
our estimates of M$_{200}$ for the galaxy from NFW models are in the range of
5.0 to 8.8 $\times$ 10$^{10}$ M$_\odot$. Comparing UGC 2162 to samples of UDGs
with HI detections show it to have amongst the smallest R$_e$ with its
M$_{HI}$/M$_{\star}$ being distinctly higher and g -- i colour slightly bluer
than typical values in those samples. We also compared HI and dark matter (DM)
halo properties of UGC 2162 with dwarf galaxies in the LITTLE THINGS sample and
find its DM halo mass and profile are within the range expected for a dwarf
galaxy. While we were unable to to determine the origin of the galaxy's present
day optical form from our study, its normal HI rotation velocity in relation to
its HI mass, HI morphology, environment and dwarf mass DM halo ruled out some
of the proposed ultra diffuse galaxy formation scenarios for this galaxy.
