An inventory of supershells in nearby galaxies: first results from THINGS

Abstract

The HI Nearby Galaxy Survey (THINGS), is a 21cm HI line survey of a sample of 34 nearby (310 Mpc) galaxies (Walter et al. 2005). The observations were carried out with the VLA and have a velocity resolution of 5 km s1 or better and an angular resolution of 7 which at this distance range corresponds to a linear resolution of 100300 pc. One of the primary goals of THINGS is to look at the finescale structure of the Interstellar Medium (ISM) and examine how it varies as a function of Hubble type, star formation rate, galaxy mass, metallicity, etc. We present one of the first science results from this project, an inventory of HI shells in the galaxies NGC 628, NGC 3184, and NGC 6946.