The Massive Star Content of Circumnuclear Star Clusters in M83

TL;DR

This study investigates the massive star content and initial mass function in circumnuclear star clusters of M83 using archival HST data and compares observations with both empirical and theoretical stellar population models.

Contribution

It provides a detailed analysis of the stellar populations in M83's star clusters by comparing observational data with new and existing stellar population models, enhancing understanding of high-metallicity environments.

Findings

Derived ages, masses, and reddenings of clusters from spectral and photometric data.

Compared empirical and theoretical models to assess their accuracy in high-metallicity environments.

Improved constraints on the massive star IMF in circumnuclear regions of M83.

Abstract

The circumnuclear starburst of M83 (NGC 5236), the nearest such example (4.6 Mpc), constitutes an ideal site for studying the massive star IMF at high metallicity (12+log[O/H]=9.1$\pm$0.2, Bresolin & Kennicutt 2002). We analyzed archival HST/STIS FUV imaging and spectroscopy of 13 circumnuclear star clusters in M83. We compared the observed spectra with two types of single stellar population (SSP) models, semi-empirical models, which are based on an empirical library of Galactic O and B stars observed with IUE (Robert et al. 1993), and theoretical models, which are based on a new theoretical UV library of hot massive stars described in Leitherer et al. (2010) and computed with WM-Basic (Pauldrach et al. 2001). The models were generated with Starburst99 (Leitherer & Chen 2009). We derived the reddenings, the ages, and the masses of the clusters from model fits to the FUV spectroscopy, as well as from optical HST/WFC3 photometry.