The Spectroscopic Properties of Lyα-Emitters at z $\approx$ 2.7: Escaping Gas and Photons from Faint Galaxies

Abstract

We present a spectroscopic survey of 318 faint $(R\sim 27$, $L\sim 0.1L_{\ast })$, Lyα-emission-selected galaxies (LAEs) at 2.5<z<3. A sample of 32 LAEs with rest-frame optical spectra from Keck/MOSFIRE are used to interpret the LAE spectra in the context of their systemic redshifts. We find that the Lyα emission of LAEs is typically less spectrally extended than among samples of more luminous continuum-selected galaxies (LBGs) at similar redshifts. Using the MOSFIRE subsample, we find that the peak of the Lyα line is shifted by +200 km/s with respect to systemic across a diverse set of galaxies including both LAEs and LBGs. We also find a small number of objects with significantly blueshifted Lyα emission, a potential indicator of accreting gas. The Lyα-to-Hα line ratios suggest that the LAEs have Lyα escape fractions $f_{\mathrm{esc},\mathrm{Ly}\alpha }\approx 30$%, significantly higher than typical LBG samples. Using redshifts calibrated by our MOSFIRE sample, we construct composite LAE spectra, finding the first evidence for metal-enriched outflows in such intrinsically-faint high-redshift galaxies. These outflows have smaller continuum covering fractions $(f_c\approx 0.3)$ and velocities $(v_{\mathrm{ave}}\approx 100-200$ km/s, $v_{\max }\approx 500$ km/s$)$ than those associated with typical LBGs, suggesting that gas covering fraction is a likely driver of the high Lyα and Ly-continuum escape fractions of LAEs. Our results suggest a similar scaling of outflow velocity with star formation rate as is observed at lower redshifts $(v_{\mathrm{outflow}}\sim {\mathrm{SFR}}^{0.25})$ and indicate that a substantial fraction of gas is ejected with $v>v_{esc}$.

References in corpus (19)

• The Mass-Metallicity Relation at z~2
• Strong Nebular Line Ratios in the Spectra of z~2-3 Star-forming Galaxies: First Results from KBSS-MOSFIRE
• Ubiquitous outflows in DEEP2 spectra of star-forming galaxies at z=1.4
• The Subaru/XMM-Newton Deep Survey (SXDS). IV. Evolution of Lya Emitters from z=3.1 to 5.7 in the 1 deg^2 Field: Luminosity Functions and AGN
• The Stellar, Gas and Dynamical Masses of Star-Forming Galaxies at z~2
• 3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies
• 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 Ly-alpha Properties of Faint Galaxies at z2-3 with Systemic Redshifts and Velocity Dispersions from Keck-MOSFIRE
• Metal-line absorption around $z\approx$2.4 star-forming galaxies in the Keck Baryonic Structure Survey
• 3D Lyman-alpha radiation transfer. III. Constraints on gas and stellar properties of z~3 Lyman break galaxies (LBG) and implications for high-z LBGs and Lyman-alpha emitters(LAEs)
• The Lyman alpha Reference Sample: Extended Lyman alpha Halos Produced at Low Dust Content
• The Lyman-alpha Reference Sample: I. Survey outline and first results for Markarian 259
• The Lyman Alpha Reference Sample: V. The impact of neutral ISM kinematics and geometry on Lyman Alpha escape
• Deficiency of large equivalent width Lyman-alpha emission in luminous Lyman break galaxies at z~5-6?
• Transverse Sizes of CIV Absorption Systems Measured from Multiple QSO Sightlines
• The LyAlpha Line Profiles of Ultraluminous Infrared Galaxies: Fast Winds and Lyman Continuum Leakage
• Confirmation of a Steep Luminosity Function for Lyman-alpha Emitters at z = 5.7: A Major Component of Reionization
• Plausible fluorescent Ly-alpha emitters around the z=3.1 QSO0420-388
• HST Emission Line Galaxies at z ~ 2: The Ly-alpha Escape Fraction

Cited by in corpus (123)

• The Universe is Reionizing at z~7: Bayesian Inference of the IGM Neutral Fraction Using Ly$\alpha$ Emission from Galaxies
• The Keck Lyman Continuum Spectroscopic Survey (KLCS): The Emergent Ionizing Spectrum of Galaxies at $z\sim 3$
• Rapid Reionization by the Oligarchs: The Case for Massive, UV-Bright, Star-Forming Galaxies with High Escape Fractions
• 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
• Tracing the reionization epoch with ALMA: [CII] emission in z~7 galaxies
• The LyA-LyC Connection: Evidence for an Enhanced Contribution of UV-faint Galaxies to Cosmic Reionization
• SILVERRUSH. III. Deep Optical and Near-Infrared Spectroscopy for Lya and UV-Nebular Lines of Bright Lya Emitters at z=6-7
• The MOSDEF Survey: Significant Evolution in the Rest-Frame Optical Emission Line Equivalent Widths of Star-Forming Galaxies at z=1.4-3.8
• A Window On The Earliest Star Formation: Extreme Photoionization Conditions of a High-Ionization, Low-Metallicity Lensed Galaxy at z~2
• Blueberry galaxies: the lowest mass young starbursts
• Measuring the Physical Conditions in High-Redshift Star-Forming Galaxies: Insights from KBSS-MOSFIRE
• The Connection Between Reddening, Gas Covering Fraction, and the Escape of Ionizing Radiation at High Redshift
• Recovering the systemic redshift of galaxies from their Lyman-alpha line profile
• Slicing COSMOS with SC4K: the evolution of typical Lya emitters and the Lya escape fraction from z~2 to z~6
• The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) Survey Design, Reductions, and Detections
• The origin of the escape of Lyman alpha and ionizing photons in Lyman Continuum Emitters
• The CALYMHA survey: Lya luminosity function and global escape fraction of Lya photons at z=2.23
• The MUSE-Wide Survey: A first catalogue of 831 emission line galaxies
• The VIMOS Ultra Deep Survey: Emerging from the Dark, a Massive Proto-Cluster at z~4.57
• Neutral gas properties of Lyman continuum emitting galaxies: column densities and covering fractions from UV absorption lines
• The CALYMHA survey: Ly$\alpha$ escape fraction and its dependence on galaxy properties at $z=2.23$
• A High-Resolution Hubble Space Telescope Study of Apparent Lyman Continuum Leakers at $z\sim 3$
• The Lyman Continuum Escape Survey -- II: Ionizing Radiation as a Function of the [OIII]/[OII] Line Ratio
• The Rest-Frame Optical Spectroscopic Properties of Ly$\alpha$-Emitters at $z\sim 2.5$: The Physical Origins of Strong Ly$\alpha$ Emission
• The Low-Redshift Lyman Continuum Survey. Unveiling the ISM properties of low-$z$ Lyman continuum emitters
• The nature of luminous Lyman-alpha emitters at z~2-3: maximal dust-poor starbursts and highly ionising AGN
• Measuring the properties of reionised bubbles with resolved Lyman alpha spectra
• Dust Attenuation, Star Formation, and Metallicity in z ~ 2-3 Galaxies from KBSS-MOSFIRE
• Spectroscopic properties of luminous Lyman-α emitters at $z\approx 6-7$ and comparison to the Lyman-break population
• The Mean Ultraviolet Spectrum of a Representative Sample of Faint z~3 Lyman Alpha Emitters
• The MUSE Hubble Ultra Deep Field Survey X. Ly$\alpha$ Equivalent Widths at $2.9<z<6.6$
• Puzzling Lyman-alpha line profiles in green pea 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
• The Effects of Stellar Population and Gas Covering Fraction on the Emergent Lyman Alpha Emission of High-Redshift Galaxies
• From Mirrors to Windows: Lyman-Alpha Radiative Transfer in a Very Clumpy Medium
• RASCAS: RAdiation SCattering in Astrophysical Simulations
• MUSEQuBES: Calibrating the redshifts of Ly α emitters using stacked circumgalactic medium absorption profiles
• The redshift evolution of rest-UV spectroscopic properties in Lyman Break Galaxies at z ~ 2-4
• A Comprehensive Study of Ly$\alpha$ Emission in the High-redshift Galaxy Population
• Resonant line transfer in a fog: Using Lyman-alpha to probe tiny structures in atomic gas
• A High Fraction of Ly-alpha-Emitters Among Galaxies with Extreme Emission Line Ratios at z ~ 2
• Three Lyman-alpha emitting galaxies within a quasar proximity zone at z=5.8
• Modeling $237$ Lyman-$\alpha$ spectra of the MUSE-Wide survey
• Fast Outflows Identified in Early Star-Forming Galaxies at $z=5-6$
• An extreme blue nugget, UV-bright starburst at z=3.613 with ninety per cent of Lyman continuum photon escape
• Spectroscopic Confirmation of a Protocluster at z=3.786
• The physics of Lyman-alpha escape from disc-like galaxies
• The UV-brightest Lyman continuum emitting star-forming galaxy
• Simulating the diversity of shapes of the Lyman-$\alpha$ line
• Lyman-alpha spectroscopy of extreme [OIII] emitting galaxies at $z\simeq 2-3$: Implications for Ly$\alpha$ visibility and LyC leakage at $z>6$
• Absorption Line Spectroscopy of Gravitationally-Lensed Galaxies: Further Constraints on the Escape Fraction of Ionizing Photons at High Redshift
• Cosmology with dropout selection: Straw-man surveys and CMB lensing
• New Methods for Identifying Lyman Continuum Leakers and Reionization-Epoch Analogues
• The ALPINE-ALMA [CII] survey: Small Lya-[CII] velocity offsets in main-sequence galaxies at 4.4 < z < 6
• Winds of change: reionization by starburst galaxies
• Searching for z > 6.5 Analogs Near the Peak of Cosmic Star Formation
• Equivalent widths of Lyman $\alpha$ emitters in MUSE-Wide and MUSE-Deep
• MUSE Spectroscopic Identifications of Ultra-Faint Emission Line Galaxies with M${}_{\mathrm{UV}}\sim$ -15
• The HDUV Survey: Six Lyman Continuum Emitter Candidates at z~2 Revealed by HST UV Imaging
• The KBSS-KCWI Survey: The connection between extended Ly$\alpha$ halos and galaxy azimuthal angle at $z\sim 2-3$
• Predicting Ly$\alpha$ Emission from Galaxies via Empirical Markers of Production and Escape in the KBSS
• Faint end of the $z\sim 3-7$ luminosity function of Lyman-alpha emitters behind lensing clusters observed with MUSE
• MUSEQuBES: Characterizing the circumgalactic medium of redshift $\approx 3.3$ Ly$\alpha$ emitters
• MUSE integral-field spectroscopy towards the Frontier Fields cluster Abell S1063: II. Properties of low luminosity Lyman alpha emitters at z>3
• Resolving on 100 pc scales the UV-continuum in Lyman-$\alpha$ emitters between redshift 2 to 3 with gravitational lensing
• Deciphering Lyman $\alpha$ blob 1 with deep MUSE observations
• The MUSE Hubble Ultra Deep Field Survey. XV. The mean rest-UV spectra of Ly-alpha emitters at z>3
• Lyman-alpha transmission properties of the intergalactic medium in the CoDaII simulation
• Predicting LyC emission of galaxies using their physical and Ly$\alpha$ emission properties
• The VANDELS survey: A strong correlation between Ly$\alpha$ equivalent width and stellar metallicity at $3\le \mathbf{z}\le 5$
• Ly$\alpha$ Emitters with Very Large Ly$\alpha$ Equivalent Widths, EW${}_0$(Ly$\alpha$) $\simeq 200-400$ Å, at $z\sim 2$
• Confirmation of double peaked Lyman-alpha emission at z=6.593: Witnessing a galaxy directly contributing to the reionisation of the Universe
• The Circumgalactic Medium of Extreme Emission Line Galaxies at z ~ 2: Resolved Spectroscopy and Radiative Transfer Modeling of Spatially Extended Lyman-alpha Emission in the KBSS-KCWI Survey
• Early Results from GLASS-JWST XXII: Rest frame UV-optical spectral properties of Lyman-alpha emitting galaxies at 3 $<$ z $<$ 6
• CECILIA: The Faint Emission Line Spectrum of z~2-3 Star-forming Galaxies
• The CGM at Cosmic Noon with KCWI: Outflows from a Star-forming Galaxy at z=2.071
• Variations of Observed Lyman-α Spectra Shapes due to the Intergalactic Absorption
• Revisiting the Gas Kinematics in SSA22 Lyman-$\alpha$ Blob 1 with Radiative Transfer Modeling in a Multiphase, Clumpy Medium
• Unlocking the Full Potential of Extragalactic Ly$\alpha$ through Its Polarization Properties
• The VIMOS Ultra Deep Survey: The role of HI kinematics and HI column density on the escape of Lyalpha photons in star-forming galaxies at 2<z<4
• Predicting Lyman-alpha escape fractions with a simple observable: Lyman-alpha in emission as an empirically calibrated star formation rate indicator
• The Detection of Intergalactic Halpha Emission from the Slug Nebula at z~2.3
• A Complex Multiphase DLA Associated with a Compact Group at z=2.431 Traces Accretion, Outflows, and Tidal Streams
• Rest-frame UV Properties of Luminous Strong Gravitationally Lensed Ly$\alpha$ Emitters from the BELLS GALLERY Survey
• Understanding large-scale structure in the SSA22 protocluster region using cosmological simulations
• Differences and similarities of stellar populations in LAEs and LBGs at $z\sim$ 3.4 - 6.8
• A new model framework for circumgalactic Ly$\alpha$ radiative transfer constrained by galaxy-Ly$\alpha$ forest clustering
• Sub-kiloparsec Imaging of Lyman-alpha Emission in a Low Mass, Highly Ionized, Gravitationally Lensed Galaxy at z = 1.84
• Lyman-Alpha Escape from Low-Mass, Compact, High-Redshift Galaxies
• The HETDEX Survey: The Ly$\alpha$ Escape Fraction from 3D-HST Emission Line Galaxies at $z\sim 2$
• Measuring the average molecular gas content of star-forming galaxies at $z=3-4$
• A double-peaked Lyman-$\alpha$ emitter with a strong blue peak multiply imaged by the galaxy cluster RXC J0018.5+1626
• The MUSE-Wide survey: Detection of a clustering signal from Lyman-α-emitters at 3<z<6
• The MOSDEF-LRIS Survey: Connection between Galactic-scale Outflows and the Properties of $z$~2 star-forming Galaxies
• LESSER: A Catalogue of Spectroscopically selected sample of Lyman-$\alpha$ Emitters Lensed By Galaxies
• Connecting Galactic Outflows and Star Formation: Inferences from H-alpha Maps and Absorption Line Spectroscopy at 1 < z < 1.5
• A $1.4$ deg${}^2$ blind survey for CII], CIII] and CIV at $\mathbf{z}\sim 0.7-1.5$. I: nature, morphologies and equivalent widths
• The Ly$\alpha$ emission from high-$z$ galaxies hosting strong Damped Ly$\alpha$ systems
• Substructure within the SSA22 protocluster at $z\approx 3.09$
• The average submillimetre properties of Lyman-alpha Blobs at z=3
• APEX at the QSO MUSEUM: molecular gas reservoirs associated with $z\sim$3 quasars and their link to the extended Ly$\alpha$ emission
• Stellar feedback in a clumpy galaxy at $z\sim$ 3.4
• Metal content of the circumgalactic medium around star-forming galaxies at z $\sim$ 2.6 as revealed by the VIMOS Ultra-Deep Survey
• The ALPINE-ALMA [CII] Survey: CGM pollution and gas mixing by tidal stripping in a merging system at z~4.57
• Introducing the Texas Euclid Survey for Lyman Alpha (TESLA) Survey: Initial Study Correlating Galaxy Properties to Lyman-Alpha Emission
• A $1.4$ deg${}^2$ blind survey for CII], CIII] and CIV at $\mathbf{z}\sim 0.7-1.5$. II: luminosity functions and cosmic average line ratios
• Probing IGM accretion onto faint Lyα emitters at z~2.8
• Determining the systemic redshift of Lyman-alpha emitters with neural networks and improving the measured large-scale clustering
• The Utility of Lyman-alpha Emission Lines as a Probe of Interactions between High Redshift Galaxies and their Environments
• The MUSE Extremely Deep Field: Classifying the Spectral Shapes of Lya Emitting Galaxies
• The JWST/AURORA Survey: Multiple Balmer and Paschen Emission Lines for Individual Star-forming Galaxies at z=1.5-4.4. I. A Diversity of Nebular Attenuation Curves and Evidence for Non-Unity Dust Covering Fractions
• A Simulated Galaxy Laboratory: Exploring the Observational Effects on UV Spectral Absorption Line Measurements
• A unique window into the Epoch of Reionisation: A double-peaked Lyman-$\alpha$ emitter in the proximity zone of a quasar at $z\sim 6.6$
• Lyman-alpha at Cosmic Noon I: Ly-alpha Spectral Type Selection of z ~ 2-3 Lyman Break Galaxies with Broadband Imaging
• KBSS-InCLOSE I: Design and First Results from the Inner CGM of QSO Line Of Sight Emitting Galaxies at z~2-3
• The Effect of Superpositions on the Planetary Nebula Luminosity Function
• Analogs of primeval galaxies two billion years after the Big Bang
• LATIS: Comparing Galaxy and IGM Tomography Maps as Tracers of Large-scale Structure and Protoclusters at $z\sim 2.5$
• CECILIA: Ultra-Deep Rest-Optical Spectra of Faint Galaxies at Cosmic Noon
• Lyman-alpha at Cosmic Noon II: The relationship between kinematics and Lyman-alpha in z~2-3 Lyman Break Galaxies
• Star-Formation in Neutral Hydrogen Gas Reservoirs at Cosmic Noon