An Hα Impression of Lyα Galaxies at $z\simeq 6$ with Deep JWST/NIRCam Imaging

Abstract

We present a study of seven spectroscopically confirmed (Ly$\alpha$ emitting) galaxies at redshift $z\simeq 6$ using the $JWST$/NIRCam imaging data. These galaxies, with a wide range of Ly$\alpha$ luminosities, were recently observed in a series of NIRCam broad- and medium-bands. We constrain the rest-frame UV/optical continua and measure the H$\alpha$ line emission of the galaxies using the combination of the $JWST$/NIRCam and archival $HST$/WFC3 infrared photometry. We further estimate their escape fractions of Ly$\alpha$ photons ($f_{\mathrm{esc}}^{\mathrm{Ly}\alpha }$) and the production efficiency of ionizing photons (${\xi }_{\mathrm{ion}}$). Among the sample, 6/7 galaxies have Ly$\alpha$ escape fractions of $\lesssim 10\%$, which might be the status for most of star-forming galaxies at $z\simeq 6$. One UV-faint Ly$\alpha$ galaxy with an extremely blue UV slope owns a large value of $f_{\mathrm{esc}}^{\mathrm{Ly}\alpha }$ reaching $\simeq 50\%$. These galaxies spread a broad range of ${\xi }_{\mathrm{ion}}$ over log${}_{10}$ ${\xi }_{\mathrm{ion},0}$ (Hz erg${}^{-1}$) $\sim 25.0-26.5$. We find that UV-fainter galaxies with bluer UV continuum slopes likely have higher escape fractions of Ly$\alpha$ photons. We also find that galaxies with higher Ly$\alpha$ line emission tend to produce ionizing photons more efficiently. The most Ly$\alpha$-luminous galaxy in the sample has a very high ${\xi }_{\mathrm{ion},0}$ of log${}_{10}$ ${\xi }_{\mathrm{ion},0}$ (Hz erg${}^{-1}$) $>26$. Our results support that Ly$\alpha$ galaxies may have served as an important contributor to the cosmic reionization. Blue and bright Ly$\alpha$ galaxies are excellent targets for $JWST$ follow-up spectroscopic observations.

arXiv commentAccepted by ApJL; an improved version

References in corpus (81)

• The Dust Content and Opacity of Actively Star-Forming Galaxies
• Star Formation in the Milky Way and Nearby Galaxies
• CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey
• CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey - The Hubble Space Telescope Observations, Imaging Data Products and Mosaics
• The James Webb Space Telescope
• The Star Formation History of Field Galaxies
• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• Cosmic Reionization and Early Star-Forming Galaxies: A Joint Analysis of New Constraints from Planck and Hubble Space Telescope
• Calibrating Extinction-Free Star Formation Rate Diagnostics with 33GHz Free-Free Emission in NGC6946
• Inferring the star-formation histories of massive quiescent galaxies with BAGPIPES: Evidence for multiple quenching mechanisms
• Dust-Corrected Star Formation Rates of Galaxies. II. Combinations of Ultraviolet and Infrared Tracers
• New Constraints on Cosmic Reionization from the 2012 Hubble Ultra Deep Field Campaign
• CANDELS Multi-wavelength Catalogs: Source Detection and Photometry in the GOODS-South Field
• Spectroscopy of Lyman Break Galaxies in the Hubble Deep Field
• The End of the Reionization Epoch Probed by Ly-alpha Emitters at z=6.5 in the Subaru Deep Field
• UV-Continuum Slopes of >4000 z~4-8 Galaxies from the HUDF/XDF, HUDF09, ERS, CANDELS-South, and CANDELS-North Fields
• Lyman-alpha and CIII] Emission in z=7-9 Galaxies: Accelerated Reionization Around Luminous Star Forming Systems?
• Spectral and Photometric Evolution of Young Stellar Populations: the Impact of Gaseous Emission at Various Metallicities
• Detection of high Lyman continuum leakage from four low-redshift compact star-forming galaxies
• Conditions for Reionizing the Universe with A Low Galaxy Ionizing Photon Escape Fraction
• CANDELS Multiwavelength catalogs: Source Identification and Photometry in the CANDELS UKIDSS Ultra-Deep Survey Field
• Using Lyman-alpha to detect galaxies that leak Lyman continuum
• Lyman Alpha Emitting Galaxies as a Probe of Reionization
• The impact of nebular emission on the ages of z~6 galaxies
• Spectroscopic detection of CIV in a galaxy at z=7.045: Implications for the ionizing spectra of reionization-era galaxies
• Ly$\alpha$ emission from Green Peas: the role of circumgalactic gas density, covering, and kinematics
• Completing the Census of Ly-alpha Emitters at the Reionization Epoch
• Lyman-alpha spectral properties of five newly discovered Lyman continuum emitters
• The Lyman-Continuum Photon Production Efficiency xi_{ion} of z~4-5 Galaxies from IRAC-based Halpha Measurements: Implications for the Escape Fraction and Cosmic Reionization
• An Atlas of z=5.7 and z=6.5 Ly alpha Emitters
• Ly$\alpha$ profile, dust, and prediction of Ly$\alpha$ escape fraction in Green Pea Galaxies
• An extreme [OIII] emitter at $z=3.2$: a low metallicity Lyman continuum source
• The MUSE Hubble Ultra Deep Field Survey: II. Spectroscopic redshifts and comparisons to color selections of high-redshift galaxies
• Q1549-C25: A Clean Source of Lyman-Continuum Emission at $z=3.15$
• The Low-Redshift Lyman Continuum Survey II: New Insights into LyC Diagnostics
• The Far-Ultraviolet Continuum Slope as a Lyman Continuum Escape Estimator at High-redshift
• First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ~ 7
• The LyA-LyC Connection: Evidence for an Enhanced Contribution of UV-faint Galaxies to Cosmic Reionization
• Direct Detection of Lyman Continuum Escape from Local Starburst Galaxies with the Cosmic Origins Spectrograph
• The Lyman alpha Reference Sample: II. HST imaging results, integrated properties and trends
• SILVERRUSH. III. Deep Optical and Near-Infrared Spectroscopy for Lya and UV-Nebular Lines of Bright Lya Emitters at z=6-7
• Keck Spectroscopy of Faint 3 < z < 7 Lyman Break Galaxies: III. The Mean Ultraviolet Spectrum at z=4
• The production and escape of Lyman-Continuum radiation from star-forming galaxies at z~2 and their redshift evolution
• SILVERRUSH. V. Census of Lya, [OIII]5007, Ha, and [CII]158um Line Emission with ~1000 LAEs at z=4.9-7.0 Revealed with Subaru/HSC
• Evidence for a Hard Ionizing Spectrum from a z=6.11 Stellar Population
• CANDELSz7: a large spectroscopic survey of CANDELS galaxies in the reionization epoch
• A Coherent Study of Emission Lines from Broad-Band Photometry: Specific Star-Formation Rates and [OIII]/Hβ Ratio at 3 < z < 6
• Evolution of the Cool Gas in the Circumgalactic Medium (CGM) of Massive Halos -- A Keck Cosmic Web Imager (KCWI) Survey of Ly$\alpha$ Emission around QSOs at $z\approx 2$
• A Hard Ionizing Spectrum in z=3-4 Ly-alpha Emitters with Intense [OIII] Emission: Analogs of Galaxies in the Reionization Era?
• The Recent Burstiness of Star Formation in Galaxies at z~4.5 from H$\alpha$ Measurements
• Diverse properties of Ly-alpha emission in low-redshift compact star-forming galaxies with extremely high [OIII]/[OII] ratios
• Semi-analytic forecasts for JWST -- IV. Implications for cosmic reionization and LyC escape fraction
• Spectroscopic properties of luminous Lyman-α emitters at $z\approx 6-7$ and comparison to the Lyman-break population
• The Star Formation Burstiness and Ionizing Efficiency of Low-mass Galaxies
• The X-SHOOTER Lyman-$\alpha$ survey at z=2 (XLS-z2) I: What makes a galaxy a Lyman-$\alpha$ emitter?
• Elevated ionizing photon production efficiency in faint high-equivalent-width Lyman-alpha emitters
• A Lyman-α protocluster at redshift 6.9
• Lyman Alpha Emitters and Lyman Break Galaxies: dichotomous twins?
• The mean H$\alpha$ EW and Lyman-continuum photon production efficiency for faint $z\approx 4-5$ galaxies
• The Lyman-continuum photon production efficiency in the high-redshift Universe
• Mean Halpha+[NII]+[SII] EW Inferred for Star-Forming Galaxies at z=5.1-5.4 Using High-Quality Spitzer/IRAC Photometry
• CLASH-VLT: spectroscopic confirmation of a z=6.11 quintuply lensed galaxy in the Frontier Fields Cluster RXC J2248.7-4431
• High Equivalent Width of Hα+[N II] Emission in z~8 Lyman-break Galaxies from IRAC 5.8μm Observations: Evidence for Efficient Lyman-continuum Photon production in the Epoch of Re-ionization
• The evolution of rest-frame UV properties, Lya EWs and the SFR-Stellar mass relation at z~2-6 for SC4K LAEs
• Definitive upper bound on the negligible contribution of quasars to cosmic reionization
• Semi-analytic forecasts for JWST -- III. Intrinsic production efficiency of Lyman-continuum radiation
• The Magellan M2FS Spectroscopic Survey of High-$z$ Galaxies: Lyα Emitters at $z\approx 6.6$ and the Evolution of Lyα Luminosity Function over $z\approx 5.7-6.6$
• The efficiency of ionising photon production and the radiation energy balance in compact star-forming galaxies
• The Ionizing Photon Production Efficiency (${\xi }_{ion}$) Of Lensed Dwarf Galaxies At $z\sim 2$
• Physical Properties of Spectroscopically-Confirmed Galaxies at $z\ge 6$. III. Stellar Populations from SED Modeling with Secure Ly$\alpha$ Emission and Redshifts
• Modelling of Lyman-alpha Emitting Galaxies and Ionized Bubbles at the Era of Reionization
• The Compact UV Size of Green Pea Galaxies As Local Analogs of High-redshift Ly$\alpha$-Emitters
• The Evolution of the Ultraluminous Ly-alpha Luminosity Function over z=5.7-6.6
• A Magellan M2FS Spectroscopic Survey of Galaxies at 5.5<z<6.8: Program Overview and a Sample of the Brightest Lyman-alpha Emitters
• The Magellan M2FS Spectroscopic Survey of High-Redshift Galaxies: A Sample of 260 Ly$\alpha$ Emitters at Redshift $z\approx 5.7$
• A Deep Ly$\alpha$ Survey in ECDF-S and COSMOS: I. General Properties of Lyman-alpha Emitters at $z\sim 2$
• The Spitzer/IRAC Legacy over the GOODS Fields: Full-Depth 3.6, 4.5, 5.8 and 8.0um Mosaics and Photometry for > 9000 Galaxies at z~3.5-10 from the GOODS Re-ionization Era wide-Area Treasury from Spitzer (GREATS)
• Luminous Lyman-alpha Emitters with Very Blue UV-continuum Slopes at Redshift 5.7 <= z <= 6.6
• Differences and similarities of stellar populations in LAEs and LBGs at $z\sim$ 3.4 - 6.8
• Diffuse Lyman-alpha Halos around ~300 Spectroscopically Confirmed Lyman-alpha Emitters at z ~ 5.7
• MUSE observations towards the lensing cluster A2744: Intersection between the LBG and LAE populations at z $\sim$ 3-7

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• MIDIS: Strong (Hb + [OIII]) and Ha emitters at redshift $z\simeq 7-8$ unveiled with JWST/NIRCam and MIRI imaging in the Hubble eXtreme Deep Field (XDF)
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• The JWST Advanced Deep Extragalactic Survey: Discovery of an Extreme Galaxy Overdensity at $z=5.4$ with JWST/NIRCam in GOODS-S
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• The Universe is at Most 88% Neutral at z=10.6
• Spatially-resolved H$\alpha$ and ionizing photon production efficiency in the lensed galaxy MACS1149-JD1 at a redshift of 9.11
• Ly-alpha emission in low-redshift most metal-deficient compact star-forming galaxies
• Unveiling Luminous Ly$\alpha$ Emitters at $z\approx 6$ through JWST/NIRCam Imaging in the COSMOS Field
• Spatially resolved H$\alpha$ emission in B14-65666: compact starbursts, ionizing efficiency and gas kinematics in an advanced merger at the Epoch of Reionization
• REBELS-IFU: Spatially Resolved Ionizing Photon Production Efficiencies of 12 Bright Galaxies in the Epoch of Reionization
• Extreme equivalent width-selected low-mass starbursts at $z=4-9$: insights into their role in cosmic reionization
• Far-infrared observations of dust in Ly$\alpha$ emitters at z=2-6