A Catalog of Holes and Shells in the Interstellar Medium of the LITTLE THINGS Dwarf Galaxies

Nau Raj Pokhrel, Caroline E. Simpson, Ioannis Bagetakos

Published 2020-06-02Version 1

We present a catalog of holes and shells in the neutral atomic hydrogen (\HI) of 41 gas-rich dwarf galaxies in LITTLE THINGS (Local Irregulars That Trace Luminosity Extremes, The \HI Nearby Galaxy Survey). We analyzed their properties as part of an investigation into the relation between star formation and structures and kinematics in the \HI of small galaxies. We confirmed 306 holes between 38 pc (our resolution limit) and 2.3 kpc, with expansion velocities up to 30 \kms. The global star formation rates measured by \Ha and FUV emission are consistent with those estimated from the energy required to create the cataloged holes in our sample. Although we found no obvious correlation between global star-formation rates and the \HI surface and volume porosities of our sample, two of the four lowest porosity galaxies and the two highest porosity galaxies have no recent star formation as measured by \Ha and FUV emission.