Metallicities of Young Massive Clusters in NGC 5236 (M83)

TL;DR

This study analyzes the metallicities of young massive clusters in galaxy NGC 5236 using integrated-light spectra, revealing a shallow metallicity gradient and consistent central metallicity with other methods, contributing to understanding galaxy chemical evolution.

Contribution

It provides new integrated-light spectroscopic measurements of young clusters in NGC 5236 and characterizes its metallicity gradient and central metallicity with high precision.

Findings

Shallow metallicity gradient of -0.37 ± 0.29 dex R_25^{-1}

Central metallicity of +0.17 ± 0.12 dex

Metallicity at R/R_25=0.4 matches stellar mass-metallicity relation

Abstract

We present integrated-light spectra of 8 Young Massive Clusters (YMCs) in the metal-rich spiral galaxy NGC 5236 (M 83). The observations were taken with the X-Shooter spectrograph on the ESO Very Large Telescope. Through the use of theoretical isochrones and synthetic integrated-light (IL) spectra we derive metallicities and study the radial metallicity gradient observed through these young populations. For the inner regions of the galaxy we observe a relatively shallow metallicity gradient of $-$0.37 $\pm$0.29 dex R$_{25}^{-1}$, agreeing with chemical evolution models with an absence of infall material and a relatively low mass loss due to winds in the inner parts of the disk. We estimate a central metallicity of [$Z$] = $+$0.17 $\pm$ 0.12 dex, finding excellent agreement with that obtained via other methods (e.g. blue supergiants and J-band). We infer a metallicity of 12+log(O/H) = 8.75 $\pm$ 0.08 dex at R/R$_{25}$ = 0.4, which fits the stellar mass-metallicity relation (MZR) compilation of blue supergiants and IL studies.