Rotational Dynamics and Star Formation in the Nearby Dwarf Galaxy NGC
  5238
  We present new HI spectral line images of the nearby low-mass galaxy NGC
5238, acquired with the Karl G. Jansky Very Large Array (VLA). Located at a
distance of 4.51+/-0.04 Mpc, NGC 5238 is an actively star-forming galaxy with
widespread H-alpha and UV continuum emission. The source is included in many
ongoing and recent nearby galaxy surveys, but until this work the spatially
resolved qualities of its neutral interstellar medium have remained unstudied.
Our HI images resolve the disk on physical scales of ~400 pc, allowing us to
undertake a detailed comparative study of the gaseous and stellar components.
The HI disk is asymmetric in the outer regions, and the areas of high HI mass
surface density display a crescent-shaped morphology that is slightly offset
from the center of the stellar populations. The HI column density exceeds 10^21
cm^-2 in much of the disk. We quantify the degree of co-spatiality of dense HI
gas and sites of ongoing star formation as traced by far-UV and H-alpha
emission. The neutral gas kinematics are complex; using a spatially-resolved
position-velocity analysis, we infer a rotational velocity of 31+/-5 km/s. We
place NGC 5238 on the baryonic Tully-Fisher relation and contextualize the
system amongst other low-mass galaxies.
