SIMBAD references

2023ApJ...957...77P - Astrophys. J., 957, 77 (2023/November-2)

Nitrogen-enriched, Highly Pressurized Nebular Clouds Surrounding a Super Star Cluster at Cosmic Noon.

PASCALE M., DAI L., McKEE C.F. and TSANG B.T.-H.

Abstract (from CDS):

Strong lensing offers a precious opportunity for studying the formation and early evolution of super star clusters that are rare in our cosmic backyard. The Sunburst Arc, a lensed Cosmic Noon galaxy, hosts a young super star cluster with escaping Lyman continuum radiation. Analyzing archival Hubble Space Telescope images and emission line data from Very Large Telescope/MUSE and X-shooter, we construct a physical model for the cluster and its surrounding photoionized nebula. We confirm that the cluster is ≲4 Myr old, is extremely massive M⋆ ∼ 107M⊙, and yet has a central component as compact as several parsecs, and we find a gas-phase metallicity Z = (0.22 ± 0.03)Z⊙. The cluster is surrounded by ≳105M⊙ of dense clouds that have been pressurized to P ∼ 109 K cm–3 by perhaps stellar radiation at within 10 pc. These should have large neutral columns NHI > 1022.8 cm–2 to survive rapid ejection by radiation pressure. The clouds are likely dusty as they show gas-phase depletion of silicon, and may be conducive to secondary star formation if NHI > 1024 cm–2 or if they sink farther toward the cluster center. Detecting strong [N III]λλ 1750,1752, we infer heavy nitrogen enrichment $\mathrm{log}({\rm{N}}/{\rm{O}})=-{0.21}_{-0.11}^{+0.10}$. This requires efficiently retaining ≳500 M⊙ of nitrogen in the high-pressure clouds from massive stars heavier than 60 M⊙ up to 4 Myr. We suggest a physical origin of the high-pressure clouds from partial or complete condensation of slow massive star ejecta, which may have an important implication for the puzzle of multiple stellar populations in globular clusters.

Abstract Copyright: © 2023. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Stellar populations - Star clusters - Galaxies

Simbad objects: 17

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