Luminous Stars in Galaxies Beyond 3 Mpc

TL;DR

This paper investigates luminous stars in galaxies beyond 3 Mpc, focusing on their role in star cluster formation and destruction, and methods to distinguish stars from clusters using new HST data.

Contribution

It introduces techniques for separating stars from clusters and identifies candidate luminous blue variables and HII regions in distant galaxies.

Findings

Identification of luminous stars in galaxies beyond 3 Mpc.

Methods for distinguishing stars from clusters.

Initial steps in analyzing stellar populations.

Abstract

I am mainly interested in the formation and destruction of young star clusters in nearby star forming galaxies such as the Antennae, M83, and M51. One of the first analysis steps is to throw out all those pesky stars that keep contaminating my young cluster samples. Recently, spurred on by our new WFC3 Early Release Science data of galaxies including M83, NGC 4214, M82, NGC 2841, and Cen A, we began taking a closer look at the stellar component. Questions we are addressing are: 1) what are the most luminous stars, 2) how can we use them to help study the destruction of star clusters and the population of the field, 3) what fraction of stars, at least the bright stars, are formed in the field, in associations, and in compact clusters. In this contribution we describe some of the beginning steps in this process. More specifically, we describe how we separate stars from clusters in our galaxies, and describe how candidate Luminous Blue Variables (LBVs) and "Single Star" HII (SSHII) regions have been identified.