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

TL;DR

This paper provides a comprehensive catalog of HI holes and shells in 41 dwarf galaxies, analyzing their properties and exploring their relation to star formation and galaxy kinematics.

Contribution

It presents the first extensive catalog of HI holes in dwarf galaxies and investigates their connection to star formation activity and interstellar medium structure.

Findings

Confirmed 306 HI holes with sizes from 38 pc to 2.3 kpc.

Star formation rates are consistent with energy needed to form the holes.

No clear correlation between star formation rates and HI porosity.

Abstract

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.