JADES: Discovery of extremely high equivalent width Lyman-alpha emission from a faint galaxy within an ionized bubble at z=7.3

Abstract

We report the discovery of a remarkable Ly$\alpha$ emitting galaxy at z = 7.2782, JADES-GS-z7-LA, with EW${}_0$(Ly$\alpha$) $=388.0\pm 88.8$Åand UV magnitude -17.0. The spectroscopic redshift is confirmed via rest-frame optical lines [O II], H$\beta$ and [O III] in its JWST/NIRSpec Micro-Shutter Assembly (MSA) spectrum. The Ly$\alpha$ line is detected in both lower resolution PRISM as well as medium resolution G140M grating spectra. The LSF-deconvolved Ly$\alpha$ FWHM in the grating is $383.9\pm 56.2$ km/s and the Ly$\alpha$ velocity offset compared to the systemic redshift is $113.3\pm 80.0$ km/s, indicative of very little neutral gas or dust within the galaxy. We estimate the Ly$\alpha$ escape fraction to be >70%. JADES-GS-z7-LA has a O32 ratio of $11.1\pm 2.2$ and a R23 ratio of $11.2\pm 2.6$, consistent with low metallicity and high ionization parameters. Deep NIRCam imaging also revealed a close companion source (separated by 0.23"), which exhibits similar photometry to that of JADES-GS-z7-LA, with a photometric excess in the F410M NIRCam image consistent with [O III]+H$\beta$ emission at the same redshift. The spectral energy distribution of JADES-GS-z7-LA indicates a "bursty" star formation history, with a low stellar mass of $\approx 10^7$ $M_{\odot }$. Assuming that the Ly$\alpha$ transmission through the intergalactic medium is the same as its measured escape fraction, an ionized region of size > 1.5 pMpc is needed to explain the high Ly$\alpha$ EW and low velocity offset compared to systemic seen in JADES-GS-z7-LA. Owing to its UV-faintness, we show that it is incapable of single-handedly ionizing a region large enough to explain its Ly$\alpha$ emission. Therefore, we suggest that JADES-GS-z7-LA (and possibly the companion source) may be a part of a larger overdensity, presenting direct evidence of overlapping ionized bubbles at $z>7$.

arXiv comment14 pages, 8 figures, Accepted for publication in A&A

References in corpus (100)

• Stellar population synthesis at the resolution of 2003
• On the variation of the Initial Mass Function
• The Global Schmidt Law in Star Forming Galaxies
• A Quantitative Comparison of SMC, LMC, and Milky Way UV to NIR Extinction Curves
• Cosmic Reionization and Early Star-Forming Galaxies: A Joint Analysis of New Constraints from Planck and Hubble Space Telescope
• Inferring the star-formation histories of massive quiescent galaxies with BAGPIPES: Evidence for multiple quenching mechanisms
• Radiative Transfer in a Clumpy Universe: III. The Nature of Cosmological Ionizing Sources
• The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope I. Overview of the instrument and its capabilities
• PyNeb: a new tool for analyzing emission lines. I. Code description and validation of results
• Dust Attenuation Curves in the Local Universe: Demographics and New Laws for Star-forming Galaxies and High-redshift Analogs
• New Constraints on Cosmic Reionization from the 2012 Hubble Ultra Deep Field Campaign
• Nebular Emission from Star-Forming Galaxies
• An updated analytic model for the attenuation by the intergalactic medium
• Spectroscopy of Lyman Break Galaxies in the Hubble Deep Field
• The evolution of the galaxy UV luminosity function at redshifts z ~ 8-15 from deep JWST and ground-based near-infrared imaging
• A new multi-field determination of the galaxy luminosity function at z=7-9 incorporating the 2012 Hubble Ultra Deep Field imaging
• JADES NIRSpec Spectroscopy of GN-z11: Lyman-$\alpha$ emission and possible enhanced nitrogen abundance in a $z=10.60$ luminous galaxy
• NIRCam Performance on JWST In Flight
• Reionization of the Intergalactic Medium and the Damping Wing of the Gunn-Peterson Trough
• The Universe is Reionizing at z~7: Bayesian Inference of the IGM Neutral Fraction Using Ly$\alpha$ Emission from Galaxies
• Lyman-alpha and CIII] Emission in z=7-9 Galaxies: Accelerated Reionization Around Luminous Star Forming Systems?
• Conditions for Reionizing the Universe with A Low Galaxy Ionizing Photon Escape Fraction
• Using Lyman-alpha to detect galaxies that leak Lyman continuum
• Spectroscopic confirmation of z~7 LBGs: probing the earliest galaxies and the epoch of reionization
• The chemical enrichment in the early Universe as probed by JWST via direct metallicity measurements at z~8
• Identification and properties of intense star-forming galaxies at redshifts z>10
• New observations of z~7 galaxies: evidence for a patchy reionization
• Lyman-alpha Emission from a Luminous z=8.68 Galaxy: Implications for Galaxies as Tracers of Cosmic Reionization
• Signatures of Stellar Reionization of the Universe
• The UV Luminosity Function of star-forming galaxies via dropout selection at redshifts z ~ 7 and 8 from the 2012 Ultra Deep Field campaign
• J1154+2443: a low-redshift compact star-forming galaxy with a 46 per cent leakage of Lyman continuum photons
• Inferences on the Timeline of Reionization at z~8 From the KMOS Lens-Amplified Spectroscopic Survey
• "Big Three Dragons": a z = 7.15 Lyman BreakGalaxy Detected in [OIII] 88 $\mu$m, [CII] 158 $\mu$m, and Dust Continuum with ALMA
• A Spectroscopic Redshift Measurement for a Luminous Lyman Break Galaxy at z=7.730 using Keck/MOSFIRE
• The assembly of "normal" galaxies at z=7 probed by ALMA
• Galaxy Formation and Reionization: Key Unknowns and Expected Breakthroughs by the James Webb Space Telescope
• Lyman-alpha spectral properties of five newly discovered Lyman continuum emitters
• The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope II. Multi-object spectroscopy (MOS)
• A JWST/NIRCam Study of Key Contributors to Reionization: The Star-forming and Ionizing Properties of UV-faint $z\sim 7-8$ Galaxies
• Can the intergalactic medium cause a rapid drop in Lyman alpha emission at z>6?
• The spectral evolution of the first galaxies. II. Spectral signatures of Lyman continuum leakage from galaxies in the reionization epoch
• Spectroscopic confirmation of two Lyman break galaxies at redshift beyond 7
• In-orbit Performance of the Near-Infrared Spectrograph NIRSpec on the James Webb Space Telescope
• On the Escape of Ionizing Radiation from Starbursts
• Constraining the neutral fraction of hydrogen in the IGM at redshift 7.5
• JADES Imaging of GN-z11: Revealing the Morphology and Environment of a Luminous Galaxy 430 Myr After the Big Bang
• JADES: Probing interstellar medium conditions at $z\sim 5.5-9.5$ with ultra-deep JWST/NIRSpec spectroscopy
• CEERS Spectroscopic Confirmation of NIRCam-Selected z > 8 Galaxy Candidates with JWST/NIRSpec: Initial Characterization of their Properties
• Tracing the reionization epoch with ALMA: [CII] emission in z~7 galaxies
• The Far-Ultraviolet Continuum Slope as a Lyman Continuum Escape Estimator at High-redshift
• The [OIII]$+$H$\beta$ Equivalent Width Distribution at z$\simeq$7: Implications for the Contribution of Galaxies to Reionization
• The LyA-LyC Connection: Evidence for an Enhanced Contribution of UV-faint Galaxies to Cosmic Reionization
• Extended ionised and clumpy gas in a normal galaxy at z=7.1 revealed by ALMA
• Lyman continuum leakage from low-mass galaxies with Mstar < 1.E8 Msun
• Texas Spectroscopic Search for Ly$\alpha$ Emission at the End of Reionization III. the Ly$\alpha$ Equivalent-width Distribution and Ionized Structures at $z>7$
• JWST NIRCam+NIRSpec: Interstellar medium and stellar populations of young galaxies with rising star formation and evolving gas reservoirs
• A First Look at the Abundance Pattern -- O/H, C/O, and Ne/O -- in $z>7$ Galaxies with JWST/NIRSpec
• The Physical Conditions of Emission-Line Galaxies at Cosmic Dawn from JWST/NIRSpec Spectroscopy in the SMACS 0723 Early Release Observations
• A spectroscopic search for AGN activity in the reionization era
• The Effects of Reionization on Lyman-alpha Galaxy Surveys
• The MOSDEF Survey: the Variation of the Dust Attenuation Curve with Metallicity
• The ultraviolet continuum slopes ($\beta$) of galaxies at $\mathbf{z}\simeq 8-16$ from JWST and ground-based near-infrared imaging
• On the Detectability of Lyman-alpha Emission in Star-forming Galaxies: The Role of Dust
• The origin of the escape of Lyman alpha and ionizing photons in Lyman Continuum Emitters
• Searching for Extremely Blue UV Continuum Slopes at $z=7-11$ in JWST/NIRCam Imaging: Implications for Stellar Metallicity and Ionizing Photon Escape in Early Galaxies
• z~2-9 Galaxies Magnified by the Hubble Frontier Field Clusters II: Luminosity Functions and Constraints on a Faint-End Turnover
• Onset of Cosmic Reionization: Evidence of An Ionized Bubble Merely 680 Myrs after the Big Bang
• First Sample of H$\alpha$+[O III] $\lambda$5007 Line Emitters at $z>6$ Through JWST/NIRCam Slitless Spectroscopy: Physical Properties and Line Luminosity Functions
• The Volume Fraction of Ionized Intergalactic Gas at Redshift z=6.5
• Measuring the properties of reionised bubbles with resolved Lyman alpha spectra
• Closing in on the sources of cosmic reionization: first results from the GLASS-JWST program
• First Insights into the ISM at $z>8$ with JWST: Possible Physical Implications of a High [O III]$\lambda 4363$/[O III]$\lambda 5007$
• The Evolution of the Lyman-Alpha Luminosity Function During Reionization
• The Impact of Scatter in the Galaxy UV Luminosity to Halo Mass Relation on Ly$\alpha$ Visibility During the Epoch of Reionization
• Ly$\alpha$-Lyman Continuum connection in 3.5 < z < 4.3 star-forming galaxies from the VUDS survey
• Revisiting the Lyman Continuum Escape Crisis: Predictions for z > 6 from Local Galaxies
• Elevated ionizing photon production efficiency in faint high-equivalent-width Lyman-alpha emitters
• The Effects of Stellar Population and Gas Covering Fraction on the Emergent Lyman Alpha Emission of High-Redshift Galaxies
• Inferring the IGM Neutral Fraction at z ~ 6-8 with Low-Luminosity Lyman Break Galaxies
• A Lyman-α protocluster at redshift 6.9
• (Re)Solving Reionization with Lyα: How Bright Lyα Emitters account for the $z\approx 2-8$ Cosmic Ionizing Background
• The ionising photon production efficiency at z~6 for Lyman-alpha emitters using JEMS and MUSE
• Strong Ly$\alpha$ Emission in an Overdense Region at $z=6.8$: A Very Large ($R\sim 3$ physical Mpc) Ionized Bubble in COSMOS?
• Strong Lyman continuum emitting galaxies show intense CIV 1550 emission
• No strong dependence of Lyman continuum leakage on physical properties of star-forming galaxies at $3.1\lesssim \mathbf{z}\lesssim 3.5$
• Spectroscopic investigation of a reionized galaxy overdensity at z=7
• A New Constraint on the Ly$\alpha$ Fraction of UV Very Bright Galaxies at Redshift 7
• The ALMA REBELS Survey: Efficient Ly$\alpha$ Transmission of UV-Bright z$\simeq$7 Galaxies from Large Velocity Offsets and Broad Line Widths
• Dust Extinction and Metallicities of Star-Forming Lyman Alpha Emitting Galaxies at Low Redshift
• Spectroscopically Confirmed Lyman-Alpha Emitters from Redshift 5 to 7 Behind Ten Galaxy Cluster Lenses
• The Prevalence of Galaxy Overdensities Around UV-Luminous Lyman $\alpha$ Emitters in the Epoch of Reionization
• The Magellan M2FS Spectroscopic Survey of High-$z$ Galaxies: Lyα Emitters at $z\approx 6.6$ and the Evolution of Lyα Luminosity Function over $z\approx 5.7-6.6$
• Strong C IV emission from star-forming galaxies: a case for high Lyman continuum photon escape
• Predicting LyC emission of galaxies using their physical and Ly$\alpha$ emission properties
• Dark-ages Reionization and Galaxy Formation Simulation XX. The Ly$\alpha$ IGM transmission properties and environment of bright galaxies during the Epoch of Reionization
• Two Modes of LyC Escape From Bursty Star Formation: Implications for [C II] Deficits and the Sources of Reionization
• Properties and redshift evolution of star-forming galaxies with high [OIII]/[OII] ratios with MUSE at 0.28<z<0.85
• Nature and Nurture? Comparing Ly$\alpha$ Detections in UV-Bright and Fainter [O III]+H$\beta$ Emitters at $z\sim 8$ With Keck/MOSFIRE
• The archival discovery of a strong Lyman-$\alpha$ and [CII] emitter at z = 7.677
• Lyman-alpha Emitters in Ionized Bubbles: Constraining the Environment and Ionized Fraction

Cited by in corpus (26)

• JADES NIRSpec Spectroscopy of GN-z11: Lyman-$\alpha$ emission and possible enhanced nitrogen abundance in a $z=10.60$ luminous galaxy
• Spectroscopic confirmation of two luminous galaxies at $z\sim 14$
• JADES NIRSpec Initial Data Release for the Hubble Ultra Deep Field: Redshifts and Line Fluxes of Distant Galaxies from the Deepest JWST Cycle 1 NIRSpec Multi-Object Spectroscopy
• The JWST-PRIMAL Legacy Survey. A JWST/NIRSpec reference sample for the physical properties and Lyman-$\alpha$ absorption and emission of $\sim 500$ galaxies at $z=5.5-13.4$
• Deciphering Lyman-$\alpha$ Emission Deep into the Epoch of Reionisation
• JADES: The star-formation and chemical enrichment history of a luminous galaxy at z~9.43 probed by ultra-deep JWST/NIRSpec spectroscopy
• Peering into cosmic reionization: the Ly$\alpha$ visibility evolution from galaxies at $z$ = 4.5-8.5 with JWST
• Identification of High-Redshift Galaxy Overdensities in GOODS-N and GOODS-S
• JADES: Primaeval Lyman-$\alpha$ emitting galaxies reveal early sites of reionisation out to redshift $z\sim 9$
• SPICE: the connection between cosmic reionisation and stellar feedback in the first galaxies
• The NIRSpec Wide GTO Survey
• The THESAN project: connecting ionized bubble sizes to their local environments during the Epoch of Reionization
• The density-bounded twilight of starbursts in the early Universe
• Anatomy of an ionized bubble: NIRCam grism spectroscopy of the $z=6.6$ double-peaked Lyman-$\alpha$ emitter COLA1 and its environment
• Hitting the slopes: A spectroscopic view of UV continuum slopes of galaxies reveals a reddening at z > 9.5
• Mapping reionization bubbles in the JWST era I: empirical edge detection with Lyman alpha emission from galaxies
• JADES Data Release 4 Paper I: Sample Selection, Observing Strategy and Redshifts of the complete spectroscopic sample
• Mapping reionization bubbles in the JWST era II: inferring the position and characteristic size of individual bubbles
• Identifying Lyα emitter candidates with Random Forest: learning from galaxies in CANDELS survey
• The Lyman-alpha and Continuum Origins Survey II: the connection between the escape of ionizing radiation and Lyman-alpha halos in star-forming galaxies
• Towards unveiling the Cosmic Reionization: the ionizing photon production efficiency (${\xi }_{ion}$) of Low-mass H$\alpha$ emitters at $z\sim 2.3$
• Reionization in Protocluster Environments at $z>7$ with JWST/NIRSpec
• Double-Peaked Ly$\alpha$ Emission during Reionization Requires Nearby Voids and a Favorable Local Ionizing Background
• Nature of High Equivalent Width Emitters in the Epoch of Reionization Revealed by JWST Medium-band Imaging
• Impact of anisotropic photon emission from sources during the epoch of reionisation
• Far-infrared observations of dust in Ly$\alpha$ emitters at z=2-6