JWST Observations of Starbursts: Massive Star Clusters in the Central Starburst of M82

TL;DR

This study uses JWST NIRCam images to identify and analyze over a thousand star cluster candidates in M82's central starburst, revealing their properties and dust extinction levels.

Contribution

First near-infrared catalog of star clusters in M82's core, with detailed mass, size, and extinction estimates, expanding previous optical surveys.

Findings

Identified 1357 star cluster candidates, mostly new discoveries.

Cluster masses range up to 10^6 solar masses.

Cluster mass function slope of 1.9 matches other galaxy studies.

Abstract

We present a near infrared (NIR) candidate star cluster catalog for the central kiloparsec of M82 based on new JWST NIRCam images. We identify star cluster candidates using the F250M filter, finding 1357 star cluster candidates with stellar masses $>10^4$ M$_\odot$. Compared to previous optical catalogs, nearly all (87%) of the candidates we identify are new. The star cluster candidates have a median intrinsic cluster radius of $\approx$1 pc and have stellar masses up to $10^6$ M$_\odot$. By comparing the color-color diagram to dust-free yggdrasil stellar population models, we estimate that the star cluster candidates have A$_{\rm V}\sim3-24$ mag, corresponding to A$_{\rm 2.5\mu m}\sim0.3-2.1$ mag. There is still appreciable dust extinction towards these clusters into the NIR. We measure the stellar masses of the star cluster candidates, assuming ages of 0 and 8 Myr. The slope of the resulting cluster mass function is $\beta=1.9\pm0.2$, in excellent agreement with studies of star clusters in other galaxies.