Studying Interstellar Shells in our Milky Way Galaxy

Abstract

The effects of generations of stars within the interstellar medium (ISM) have produced a turbulent, multiphase medium whose evolution has shaped how solar systems like our own form within a galaxy. It is clear that the distribution of energy and material in the ISM of our Milky Way Galaxy is largely driven by the stellar winds and supernova explosions of dying stars, forming hot, expanding bubbles that sweep up shells of neutral material. These Interstellar shells gradually cool, slow down, and mix with the ambient ISM, however we still lack a complete picture of the relevant interstellar processes. Studies of numerous shells are required to improve our understanding of their role in the evolution of our Galaxy. The author and undergraduate students have searched the SETHI radio survey database for new shells. In this project, the properties of 76 such shells were explored to evaluate their suitability for (1) follow-up multi- wavelength imaging and (2) follow-up absorption-line spectroscopic studies. These investigations of interstellar shells will improve our understanding of their properties, characteristics, and interactions with the surrounding ISM.