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

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 >10⁴ M _⊙. 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 ≈1 pc and stellar masses up to 10⁶ M _⊙. By comparing the color–color diagram to dust-free YGGDRASIL stellar population models, we estimate that the star cluster candidates have A _V ∼ 3‑24 mag, corresponding to A _2.5μm ∼ 0.3‑2.1 mag. There is still appreciable dust extinction toward 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 β = 1.9 ± 0.2, in excellent agreement with studies of star clusters in other galaxies.