English

Little Red Dots as Globular Clusters in Formation

Astrophysics of Galaxies 2026-02-24 v2 Cosmology and Nongalactic Astrophysics Solar and Stellar Astrophysics

Abstract

Little Red Dots (LRDs), among the most enigmatic high-redshift discoveries by JWST, are commonly believed to be powered by accreting supermassive black holes. Here, we explore the possibility that these sources are globular clusters in formation, with rest-frame UV arising from a very young stellar population and rest-frame optical from a short-lived supermassive (>104>10^4 M_\odot) star. The spectral profiles of LRDs are broadly consistent with this scenario, though the observed temperatures and bolometric luminosities favor emission reprocessed by optically thick, continuum-driven winds not fully captured by current models. The LRD z57z\sim5-7 UV luminosity function naturally evolves, under standard evolutionary and mass-loss prescriptions, into a present-day mass function with a turnover at log10(M\log_{10}(M_\ast/M)=5.3M_\odot)=5.3 and an exponential cutoff at high masses, consistent with local globular-cluster populations. We estimate the total present-day number density of LRDs formed across all redshifts to be 0.3\approx0.3 Mpc3^{-3}, similar to local globular clusters. The observed LRD redshift range matches the age distribution of metal-poor globular clusters, without current LRD counterparts to the metal-rich population. If LRDs are globular clusters in formation, we predict chemical abundance patterns characteristic of multiple stellar populations, including enhanced He and N, and potential Na-O and Al-Mg anti-correlations. These results offer a local perspective to explore this surprisingly abundant population of distant sources, and a potential new window into extreme stellar astrophysics in the early Universe.

Keywords

Cite

@article{arxiv.2602.15935,
  title  = {Little Red Dots as Globular Clusters in Formation},
  author = {John Chisholm and Danielle A. Berg and Michael Boylan-Kolchin and Anna de Graaff and Lukas J. Furtak and Vasily Kokorev and Jorryt Matthee and Julian B. Muñoz and Rohan P. Naidu and Andreas A. C. Sander},
  journal= {arXiv preprint arXiv:2602.15935},
  year   = {2026}
}

Comments

8 pages, 4 figures

R2 v1 2026-07-01T10:40:29.328Z