Clues on the presence and segregation of very massive stars in the Sunburst Lyman-continuum cluster at z=2.37

Abstract

We report the identification of very massive stars (VMS; mass $>100$\,\msun) that may be segregated in the center of the young massive star cluster at $z$=2.37 hosted in the lensed galaxy called {\tt Sunburst} galaxy. This result is based on two pieces of evidence: (1) VLT/MUSE spectra of several multiple images of the same star cluster show key spectral signatures of VMS, such as the \heii\ broad emission, \nivblue\ emission, and an \niv\ P-Cygni profile. In particular, \heii\ is broad ($\sim 1610\pm 300$ \kms), with an equivalent width of 3Å,\ and asymmetric profile. These features require an extremely young ($\sim 2.5$ Myr) stellar population component in which the masses of the stars exceed 100~\msun. When a Salpeter initial mass function and BPASS models for normal massive stars are assumed, the observed spectral features require $\sim$400 VMS. (2) The same star cluster is detected at a signal-to-noise ratio of~$\sim 100$ in the Lyman continuum domain ($\lambda <900$Å). The Lyman continuum emission emerges from a region with a radius that is at least twice smaller than what is observed at 1700Å~(independently of magnification) and is located in the center of the cluster. After delensing, the effective radii in absolute scales are R${}_{\mathtt{eff}}[\mathtt{LyC}]\sim 4.7\pm 1.5$ pc and R${}_{\mathtt{eff}}[1700]=7.8\pm 1.4$ pc. The Lyman continuum radiation is mainly produced by hot and massive stars, which implies that their spatial distribution (including that of VMS) is preferentially more confined in the central parts of the cluster. Approximately 400 VMS hosted by a cluster of $\sim 10^7$ \msun\ produce $\sim$15\% of the escaping Lyman continuum photons, and the remaining photons are produced by other massive early-type stars.

arXiv comment10 pages, 8 figures, Accepted to publication in A&A

References in corpus (51)

• Detailed Decomposition of Galaxy Images. II. Beyond Axisymmetric Models
• The Formation of the First Star in the Universe
• Young massive star clusters
• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• The O3N2 and N2 abundance indicators revisited: improved calibrations based on CALIFA and Te-based literature data
• The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 Msun stellar mass limit
• Reevaluating Old Stellar Populations
• The Effects of Stellar Rotation. II. A Comprehensive Set of Starburst99 Models
• Evolution and fate of very massive stars
• The R136 star cluster dissected with Hubble Space Telescope/STIS. I. Far-ultraviolet spectroscopic census and the origin of HeII 1640 in young star clusters
• Galaxies with Wolf-Rayet signatures in the low-redshift Universe - A survey using the Sloan Digital Sky Survey
• The most massive stars in the Arches cluster
• Wind modelling of very massive stars up to 300 solar masses
• Paving the way for the JWST: witnessing globular cluster formation at z>3
• The Initial Mass Function of the Massive Star-forming Region NGC 3603 from Near-Infrared Adaptive Optics observations
• The evolution of rotating very massive stars with LMC composition
• The VLT-FLAMES Tarantula Survey - XI. A census of the hot luminous stars and their feedback in 30 Doradus
• Spectral Modelling of Star-Forming Regions in the Ultraviolet: Stellar Metallicity Diagnostics for High Redshift Galaxies
• Constraining the metallicities, ages, star formation histories, and ionizing continua of extragalactic massive star populations
• Gravitational lensing reveals ionizing ultraviolet photons escaping from a distant galaxy
• The effect of stellar evolution uncertainties on the rest-frame ultraviolet stellar lines of CIV and HeII in high-redshift Lyman-break galaxies
• High-resolution spectroscopy of a young, low-metallicity optically-thin L=0.02L* star-forming galaxy at z=3.12
• Ionising the Intergalactic Medium by Star Clusters: The first empirical evidence
• Dynamical Mass Estimates for Two Luminous Star Clusters in Galactic Merger Remnants
• The Sunburst Arc: Direct Lyman α escape observed in the brightest known lensed galaxy
• High star cluster formation efficiency in the strongly lensed Sunburst Lyman-continuum galaxy at z=2.37
• Star Formation at z=2.481 in the Lensed Galaxy SDSS J1110+6459: Star Formation down to 30 parsec scales
• Hubble Tarantula Treasury Project: Unraveling Tarantula's Web. II. Optical and Near Infrared Star Formation History of the Starburst Cluster NGC 2070 in 30 Doradus
• The MUSE Deep Lensed Field on the Hubble Frontier Field MACS~J0416
• The Very Massive Star Content of the Nuclear Star Clusters in NGC 5253
• The Brightest Young Star Clusters in NGC 5253
• Exploring the physical properties of lensed star-forming clumps at $2\lesssim z\lesssim 6$
• Early results from GLASS-JWST. VII: evidence for lensed, gravitationally bound proto-globular clusters at z=4 in the Hubble Frontier Field A2744
• The Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas (MEGaSaURA) I: The Sample and the Spectra
• Narrow He II emission in star-forming galaxies at low metallicity. Stellar wind emission from a population of Very Massive Stars
• Ultraviolet spectra of extreme nearby star-forming regions: evidence for an overabundance of very massive stars
• The Arches cluster out to its tidal radius: dynamical mass segregation and the effect of the extinction law on the stellar mass function
• Mass loss and the Eddington parameter: a new mass-loss recipe for hot and massive stars
• The Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas (MEGaSaURA) II: Stacked Spectra
• Spectroscopic evolution of very massive stars at Z = 1/2.5 Zsun
• Dynamical masses of two young globular clusters in the blue compact galaxy ESO 338-IG04
• A Rare Encounter with Very Massive Stars in NGC 3125-A1
• Physical Properties of II Zw 40's Super Star Cluster and Nebula: New Insights and Puzzles from UV Spectroscopy
• The connection between galactic outflows and the escape of ionizing photons
• Physics and evolution of the most massive stars in 30 Dor. Mass loss, envelope inflation, and a variable upper stellar mass limit
• Star Formation at z=2.481 in the Lensed Galaxy SDSS J1110+6459, II: What is missed at the normal resolution of the Hubble Space Telescope?
• The Cosmic Telescope that Lenses the Sunburst Arc, PSZ1 G311.65-18.48: Strong Gravitational Lensing model and Source Plane Analysis
• Probing the circum-stellar medium 2.8 Gyr after the Big Bang: detection of Bowen fluorescence in the Sunburst arc
• On the effects of the Initial Mass Function on Galactic chemical enrichment
• The Three Young Nuclear Super Star Clusters in NGC 5253
• High contrast and resolution near infrared photometry of the core of R136

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• Nitrogen-enriched, highly-pressurized nebular clouds surrounding a super star cluster at cosmic noon
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