Metal-Enriched Neutral Gas Reservoir around a Strongly-lensed, Low-mass Galaxy at $z=4$ Identified by JWST/NIRISS and VLT/MUSE

Abstract

Direct observations of low-mass, low-metallicity galaxies at $z\gtrsim 4$ provide an indispensable opportunity for detailed inspection of the ionization radiation, gas flow, and metal enrichment in sources similar to those that reionized the Universe. Combining the James Webb Space Telescope (JWST), VLT/MUSE, and ALMA, we present detailed observations of a strongly lensed, low-mass ($\approx 10^{7.6}$ ${\mathrm{M}}_{\odot }$) galaxy at $z=3.98$ (also see Vanzella et al. 2022). We identify strong narrow nebular emission, including CIV $\lambda \lambda 1548,1550$, HeII $\lambda 1640$, OIII] $\lambda \lambda 1661,1666$, [NeIII] $\lambda 3868$, [OII] $\lambda 3727$, and Balmer series of Hydrogen from this galaxy, indicating a metal-poor HII region ($\lesssim 0.12{\mathrm{Z}}_{\odot }$) powered by massive stars. Further, we detect a metal-enriched damped Ly$\alpha$ system (DLA) associated with the galaxy with the HI column density of $N_{\mathrm{HI}}\approx 10^{21.8}$ cm${}^{-2}$. The metallicity of the associated DLA may reach the super solar metallicity (${\gtrsim Z}_{\odot }$). Moreover, thanks to JWST and gravitational lensing, we present the resolved UV slope ($\beta$) map at the spatial resolution of $\approx 100$ pc at $z=4$, with steep UV slopes reaching $\beta \approx -2.5$ around three star-forming clumps. Combining with low-redshift analogs, our observations suggest that low-mass, low-metallicity galaxies, which dominate reionization, could be surrounded by a high covering fraction of the metal-enriched, neutral-gaseous clouds. This implies that the metal enrichment of low-mass galaxies is highly efficient, and further support that in low-mass galaxies, only a small fraction of ionizing radiation can escape through the interstellar or circumgalactic channels with low column-density neutral gas.

4 figures, 1 table; Accepted for Publication in the ApJL

References in corpus (25)

• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• The MAPPINGS III Library of Fast Radiative Shock Models
• Multi-Wavelength Constraints on the Cosmic Star Formation History from Spectroscopy: the Rest-Frame UV, H-alpha, and Infrared Luminosity Functions at Redshifts 1.9<z<3.4
• The MUSE Hubble Ultra Deep Field Survey: I. Survey description, data reduction and source detection
• Modelling the nebular emission from primeval to present-day star-forming galaxies
• Metallicity Evolution of Damped Lyman-alpha Systems out to z~5
• The MOSDEF Survey: The Evolution of the Mass-Metallicity Relation from $z=0$ to $z\sim 3.3$
• The GLASS James Webb Space Telescope Early Release Science Program. I. Survey Design and Release Plans
• Ultraviolet Emission Lines in Young Low Mass Galaxies at z~2: Physical Properties and Implications for Studies at z>7
• Ultraviolet spectra of extreme nearby star-forming regions --- approaching a local reference sample for JWST
• An Atlas of MUSE Observations towards Twelve Massive Lensing Clusters
• Evidence for a Hard Ionizing Spectrum from a z=6.11 Stellar Population
• JWST Noise Floor I: Random Error Sources in JWST NIRCam Time Series
• A connection between extremely strong Damped Lyman-alpha Systems and Lyman-alpha Emitting Galaxies at small impact parameters
• Strong Lyman continuum emitting galaxies show intense CIV 1550 emission
• On the Perils of Curve-of-Growth Analysis: Systematic Abundance Underestimates for the Gas in Gamma-Ray Burst Host Galaxies
• Investigating Nearby Star-Forming Galaxies in the Ultraviolet with HST/COS Spectroscopy. I: Spectral Analysis and Interstellar Abundance Determinations
• Reconciling escape fractions and observed line emission in Lyman-continuum-leaking galaxies
• Assessing the sources of reionisation: a spectroscopic case study of a 30$\times$ lensed galaxy at $z\sim 5$ with Lyα, CIV, MgII, and [NeIII]
• Neutral Gas Properties and Ly$\alpha$ Escape in Extreme Green Pea Galaxies
• A gravitationally-boosted MUSE survey for emission-line galaxies at z>~5 behind the massive cluster RCS 0224
• ALMA Lensing Cluster Survey: ALMA-Herschel Joint Study of Lensed Dusty Star-Forming Galaxies across $z\simeq 0.5-6$
• Low-mass galaxy formation and the ionizing photon budget during reionization
• Luminous Lyman-alpha Emitters with Very Blue UV-continuum Slopes at Redshift 5.7 <= z <= 6.6
• A Sub-Damped Ly$\alpha$ Absorber with Unusual Abundances: Evidence of Gas Recycling in a Low-Redshift Galaxy Group

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• A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): JWST Discovers an Overdensity around a Metal Absorption-selected Galaxy at $z\sim 5.5$
• A two-phase model of galaxy formation: III. The formation of globular clusters
• The COSMOS-Web Lens Survey (COWLS) III: forecasts versus data
• Cloudy with a chance of starshine: Possible photometric signatures of nebular-dominated emission in $1.5<z<8.5$ JADES galaxies
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