First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ~ 7

Abstract

We present the first results from the ongoing LAGER project (Lyman Alpha Galaxies in the Epoch of Reionization), which is the largest narrowband survey for $z\sim$ 7 galaxies to date. Using a specially built narrowband filter NB964 for the superb large-area Dark-Energy Camera (DECam) on the NOAO/CTIO 4m Blanco telescope, LAGER has collected 34 hours NB964 narrowband imaging data in the 3 deg${}^2$ COSMOS field. We have identified 23 Lyman Alpha Emitter (LAE) candidates at $z$ = 6.9 in the central 2-deg${}^2$ region, where DECam and public COSMOS multi-band images exist. The resulting luminosity function can be described as a Schechter function modified by a significant excess at the bright end (4 galaxies with $L_{Ly\alpha }\sim$ 10${}^{43.4\pm 0.2}$ erg s${}^{-1}$). The number density at $L_{Ly\alpha }\sim$ 10${}^{43.4\pm 0.2}$ erg s${}^{-1}$ is little changed from z= 6.6, while at fainter $L_{Ly\alpha }$ it is substantially reduced. Overall, we see a fourfold reduction in Ly$\alpha$ luminosity density from $z$ = 5.7 to 6.9. Combined with a more modest evolution of the continuum UV luminosity density, this suggests a factor of $\sim 3$ suppression of Ly$\alpha$ by radiative transfer through the $z\sim$ 7 intergalactic medium (IGM). It indicates an IGM neutral fraction $x_{HI}$ $\sim$ 0.4--0.6 (assuming Ly$\alpha$ velocity offsets of 100-200 km s${}^{-1}$). The changing shape of the Ly$\alpha$ luminosity function between $z\lesssim 6.6$ and $z=6.9$ supports the hypothesis of ionized bubbles in a patchy reionization at $z\sim$ 7.

arXiv comment7 pages, 3 figures (updated), 2 tables (updated), Accepted for publication in ApJ Letters

References in corpus (55)

• Planck 2015 results. XIII. Cosmological parameters
• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• UltraVISTA: a new ultra-deep near-infrared survey in COSMOS
• The Evolution of the Galaxy Rest-Frame Ultraviolet Luminosity Function Over the First Two Billion Years
• Statistics of 207 Lya Emitters at a Redshift Near 7: Constraints on Reionization and Galaxy Formation Models
• 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
• A Public Ks-selected Catalog in the COSMOS/UltraVISTA Field: Photometry, Photometric Redshifts and Stellar Population Parameters
• Lyman-alpha and CIII] Emission in z=7-9 Galaxies: Accelerated Reionization Around Luminous Star Forming Systems?
• Luminosity functions of Lyman-alpha emitters at z=6.5, and z=5.7: evidence against reionization at z=6
• Evidence for PopIII-like stellar populations in the most luminous Lyman-$\alpha$ emitters at the epoch of re-ionisation: spectroscopic confirmation
• A galaxy at a redshift z = 6.96
• Line Emitting Galaxies Beyond a Redshift of 7: An Improved Method for Estimating the Evolving Neutrality of the Intergalactic Medium
• Studying Reionization with Ly-alpha Emitters
• High Resolution Linear Polarimetric Imaging for the Event Horizon Telescope
• Completing the Census of Ly-alpha Emitters at the Reionization Epoch
• Probing reionization with Lyman-alpha emission lines
• How neutral is the intergalactic medium surrounding the redshift z=7.085 quasar ULAS J1120+0641?
• Subaru high-z exploration of low-luminosity quasars (SHELLQs). I. Discovery of 15 quasars and bright galaxies at 5.7 < z < 6.9
• The bright end of the galaxy luminosity function at z ~ 7: before the onset of mass quenching?
• The SDSS Coadd: 275 deg^2 of Deep SDSS Imaging on Stripe 82
• Spectroscopic detections of CIII]1909 at z~6-7: A new probe of early star forming galaxies and cosmic reionisation
• An Atlas of z=5.7 and z=6.5 Ly alpha Emitters
• Identification of the brightest Lyα emitters at z=6.6: implications for the evolution of the luminosity function in the re-ionisation era
• Accelerated Evolution of Ly$\alpha$ Luminosity Function at $\text{z}\gtrsim 7$ Revealed by the Subaru Ultra-Deep Survey for Ly$\alpha$ Emitters at $\text{z}=7.3$
• Tracing the reionization epoch with ALMA: [CII] emission in z~7 galaxies
• The Reionization and Galaxy Evolution Probed by z=7 Lyman Alpha Emitters
• Star formation and the interstellar medium in z>6 UV-luminous Lyman-break galaxies
• The First Systematic Survey for Lyman Alpha Emitters at z=7.3 with Red-sensitive Subaru/Suprime-Cam
• Lyman Alpha Emitters at Redshift z=5.7
• Evidence for a Hard Ionizing Spectrum from a z=6.11 Stellar Population
• Lyman-alpha emitters gone missing: evidence for late reionization?
• The Effects of Reionization on Lyman-alpha Galaxy Surveys
• Luminosity Functions of Lyman Alpha Emitting Galaxies and Cosmic Reionization of Hydrogen
• The Lyman-alpha luminosity function at z=5.7-6.6 and the steep drop of the faint end: implications for reionization
• On the Use of Ly-alpha Emitters as Probes of Reionization
• No galaxy left behind: accurate measurements with the faintest objects in the Dark Energy Survey
• Lyman Alpha Emitters at z=7 in the Subaru/XMM-Newton Deep Survey Field: Photometric Candidates and Luminosity Function
• The Volume Fraction of Ionized Intergalactic Gas at Redshift z=6.5
• Constraining Reionization with the Evolution of the Luminosity Function of Lyman Alpha mitting Galaxies
• Physical Properties of Spectroscopically-Confirmed Galaxies at z >= 6. I. Basic Characteristics of the Rest-Frame UV Continuum and Lyman-alpha emission
• A Galaxy at z = 6.545 and Constraints on the Epoch of Reionization
• The Luminosity Function of Lyman alpha Emitters at Redshift z=7.7
• Fisher Matrices and Confidence Ellipses: A Quick-Start Guide and Software
• The Brightest Ly$\alpha$ Emitter: Pop III or Black Hole?
• Spectroscopic observation of Ly$\alpha$ emitters at z~7.7 and implications on re-ionization
• Limits on the luminosity function of Ly-alpha emitters at z = 7.7
• First results from Faint Infrared Grism Survey (FIGS): first simultaneous detection of Lyman-alpha emission and Lyman break from a galaxy at z=7.51
• First Spectroscopic Confirmations of z ~ 7.0 Lya Emitting Galaxies in the LAGER Survey
• Searching for z~7.7 Lyman Alpha Emitters in the COSMOS Field with NEWFIRM
• A High Space Density of Luminous Lyman Alpha Emitters at z~6.5
• Lyman-Alpha Emitter Galaxies at z ~ 2.8 in the Extended Chandra Deep Field-South: I. Tracing the Large-Scale Structure via Lyman-Alpha Imaging
• A Lyman Alpha Galaxy at Redshift z=6.944 in the COSMOS Field
• Search for z~7 Ly-alpha emitters with Suprime-Cam at the Subaru Telescope
• Search for z~6.96 Ly-alpha emitters with Magellan/IMACS in the COSMOS field

Cited by in corpus (117)

• An 800-million-solar-mass black hole in a significantly neutral Universe at redshift 7.5
• The Universe is Reionizing at z~7: Bayesian Inference of the IGM Neutral Fraction Using Ly$\alpha$ Emission from Galaxies
• Conditions for Reionizing the Universe with A Low Galaxy Ionizing Photon Escape Fraction
• Inferences on the Timeline of Reionization at z~8 From the KMOS Lens-Amplified Spectroscopic Survey
• Systematic Identification of LAEs for Visible Exploration and Reionization Research Using Subaru HSC (SILVERRUSH). I. Program Strategy and Clustering Properties of ~2,000 Lya Emitters at z=6-7 over the 0.3-0.5 Gpc${}^2$ Survey Area
• Consistent modelling of the meta-galactic UV background and the thermal/ionization history of the intergalactic medium
• Texas Spectroscopic Search for Ly$\alpha$ Emission at the End of Reionization III. the Ly$\alpha$ Equivalent-width Distribution and Ionized Structures at $z>7$
• Star formation histories of dwarf galaxies in the FIRE simulations: dependence on mass and Local Group environment
• Blueberry galaxies: the lowest mass young starbursts
• JWST UNCOVER: Extremely red and compact object at$z_{\mathrm{phot}}\simeq 7.6$ triply imaged by Abell 2744
• Slicing COSMOS with SC4K: the evolution of typical Lya emitters and the Lya escape fraction from z~2 to z~6
• First results on the Epoch of Reionization from First Light with SARAS 2
• Quantifying the non-Gaussianity in the EoR 21-cm signal through bispectrum
• The nature of luminous Lyman-alpha emitters at z~2-3: maximal dust-poor starbursts and highly ionising AGN
• Onset of Cosmic Reionization: Evidence of An Ionized Bubble Merely 680 Myrs after the Big Bang
• Finding Peas in the Early Universe with JWST
• MMT Spectroscopy of Lyman-alpha at z$\simeq$7: Evidence for Accelerated Reionization Around Massive Galaxies
• Spectroscopic properties of luminous Lyman-α emitters at $z\approx 6-7$ and comparison to the Lyman-break population
• The Evolution of the Lyman-Alpha Luminosity Function During Reionization
• A New Constraint on Reionization from Evolution of the Ly$\alpha$ Luminosity Function at $z\sim 6-7$ Probed by a Deep Census of $z=7.0$ Ly$\alpha$ Emitter Candidates to 0.3 $L^{\ast }$
• SILVERRUSH. VI. A simulation of Ly$\alpha$ emitters in the reionization epoch and a comparison with Subaru Hyper Suprime-Cam survey early data
• The X-SHOOTER Lyman-$\alpha$ survey at z=2 (XLS-z2) I: What makes a galaxy a Lyman-$\alpha$ emitter?
• Searching for Islands of Reionization: A Potential Ionized Bubble Powered by a Spectroscopic Overdensity at z = 8.7
• A Lyman-α protocluster at redshift 6.9
• LAGER Ly$\alpha$ Luminosity Function at $z\sim 7$, Implications for Reionization
• Morphologies of ~190,000 Galaxies at z=0-10 Revealed with HST Legacy Data. III. Continuum Profile and Size Evolution of Lya Emitters
• The Epoch of IGM heating by early sources of X-rays
• The Ly$\alpha$ Luminosity Function and Cosmic Reionization at $z\sim$ 7.0: a Tale of Two LAGER Fields
• Three Lyman-alpha emitting galaxies within a quasar proximity zone at z=5.8
• Complex Lyman Alpha Profiles in Redshift 6.6 Ultraluminous Lyman Alpha Emitters
• Public Release of A-SLOTH: Ancient Stars and Local Observables by Tracing Halos
• On the nature and physical conditions of the luminous Lya emitter CR7 and its rest-frame UV components
• CHORUS II. Subaru/HSC Determination of the Ly$\alpha$ Luminosity Function at $z=7.0$: Constraints on Cosmic Reionization Model Parameter
• Lyman-alpha emitters gone missing: the different evolution of the bright and faint populations
• Lyman-$\alpha$ as a tracer of cosmic reionisation in the SPHINX radiation-hydrodynamics cosmological simulation
• Modelling the observed luminosity function and clustering evolution of Lyman-$\alpha$ emitters: growing evidence for late reionization
• The ALMA REBELS Survey: Efficient Ly$\alpha$ Transmission of UV-Bright z$\simeq$7 Galaxies from Large Velocity Offsets and Broad Line Widths
• SILVERRUSH. II. First Catalogs and Properties of ~2,000 Lya Emitters and Blobs at z~6-7 Identified over the 14-21 deg2 Sky
• Lyman-alpha spectroscopy of extreme [OIII] emitting galaxies at $z\simeq 2-3$: Implications for Ly$\alpha$ visibility and LyC leakage at $z>6$
• Peering into cosmic reionization: the Ly$\alpha$ visibility evolution from galaxies at $z$ = 4.5-8.5 with JWST
• First Spectroscopic Confirmations of z ~ 7.0 Lya Emitting Galaxies in the LAGER Survey
• The Magellan M2FS Spectroscopic Survey of High-$z$ Galaxies: Lyα Emitters at $z\approx 6.6$ and the Evolution of Lyα Luminosity Function over $z\approx 5.7-6.6$
• Validation of EDGES Low-Band Antenna Beam Model
• SILVERRUSH XI: Constraints on the Ly$\alpha$ luminosity function and cosmic reionization at $z=7.3$ with Subaru/Hyper Suprime-Cam
• Two Thresholds for Globular Cluster Formation and their Dominance of Star Formation in the Early-Universe
• Crucial Factors for Lyα Transmission in the Reionizing Intergalactic Medium: Infall Motion, HII Bubble Size, and Self-shielded Systems
• Discovery of a z = 7.452 High Equivalent Width Lyman-α Emitter from the Hubble Space Telescope Faint Infrared Grism Survey
• The Shape and Size distribution of HII Regions near the percolation transition
• Studying the morphology of HI isodensity surfaces during reionization using Shapefinders and percolation analysis
• Semi-analytic forecasts for Roman -- the beginning of a new era of deep-wide galaxy surveys
• An Hα Impression of Lyα Galaxies at $z\simeq 6$ with Deep JWST/NIRCam Imaging
• Texas Spectroscopic Search for Ly$\alpha$ Emission at the End of Reionization I. Constraining the Ly$\alpha$ Equivalent Width Distribution at 6.0 < $z$ < 7.0
• Confirmation of double peaked Lyman-alpha emission at z=6.593: Witnessing a galaxy directly contributing to the reionisation of the Universe
• The Ultraluminous Lyman Alpha Luminosity Function at z=6.6
• The impact of non-Gaussianity on the error covariance for observations of the Epoch of Reionization 21-cm power spectrum
• A Magellan M2FS Spectroscopic Survey of Galaxies at 5.5<z<6.8: Program Overview and a Sample of the Brightest Lyman-alpha Emitters
• Predictions for measuring the 21-cm multi-frequency angular power spectrum using SKA-Low
• A large, deep 3 deg${}^2$ survey of H$\alpha$, [OIII], and [OII] emitters from LAGER: constraining luminosity functions
• First HETDEX Spectroscopic Determinations of Ly$\alpha$ and UV Luminosity Functions at $z=2-3$: Bridging a Gap Between Faint AGN and Bright Galaxies
• Probing the thermal history during reionization using a semi-numerical photon-conserving code SCRIPT
• 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 $z\sim 2$
• Texas Spectroscopic Search for Ly$\alpha$ Emission at the End of Reionization II. The Deepest Near-Infrared Spectroscopic Observation at $z\gtrsim 7$
• The impact of non-Gaussianity on the Epoch of Reionization parameter forecast using 21-cm power spectrum measurements
• Luminous Lyman-alpha Emitters with Very Blue UV-continuum Slopes at Redshift 5.7 <= z <= 6.6
• CLEAR: Boosted Ly$\alpha$ Transmission of the Intergalactic Medium in UV bright Galaxies
• SILVERRUSH. IX. Lya Intensity Mapping with Star-Forming Galaxies at z=5.7 and 6.6: A Possible Detection of Extended Lya Emission at $\gtrsim$100 comoving kpc around and beyond the Virial-Radius Scale of Galaxy Dark Matter Halos
• Saas-Fee Lecture Notes: Physics of Lyman Alpha Radiative Transfer
• A-SLOTH reveals the nature of the first stars
• The Size and Pervasiveness of Ly$\alpha$-UV Spatial Offsets in Star-Forming Galaxies at $z\sim 6$
• Constraining the reionization and thermal history of the Universe using a semi-numerical photon-conserving code SCRIPT
• Constraining Reionization in Progress at z=5.7 with Lyman-$\alpha$ Emitters: Voids, Peaks, and Cosmic Variance
• CDIM: Cosmic Dawn Intensity Mapper Final Report
• Astraeus VIII: A new framework for Lyman-$\alpha$ emitters applied to different reionisation scenarios
• CHORUS. I. Cosmic HydrOgen Reionization Unveiled with Subaru: Overview
• Revisiting the [C II]${}_{158\mu \text{m}}$ line-intensity mapping power spectrum from the EoR using non-uniform line-luminosity scatter
• Unveiling Luminous Ly$\alpha$ Emitters at $z\approx 6$ through JWST/NIRCam Imaging in the COSMOS Field
• Late-end reionization with ATON-HE: towards constraints from Lyman-$\alpha$ emitters observed with JWST
• The Merian Survey: Design, Construction, and Characterization of a Filter Set Optimized to Find Dwarf Galaxies and Measure their Dark Matter Halo Properties with Weak Lensing
• Finding bright $z\ge 6.6$ Lyman-$\alpha$ emitters with lensing: prospects for Euclid
• ODIN: Improved Narrowband Ly$\alpha$ Emitter Selection Techniques for $z$ = 2.4, 3.1, and 4.5
• SHARDS Frontier Fields: Physical properties of a low mass Lyman-alpha emitter at z=5.75
• The Lyman Alpha Reference Sample XI: Efficient Turbulence Driven Lyα Escape and the Analysis of IR, CO and [C II]158 μm
• Design for the First Narrowband Filter for the Dark Energy Camera: Optimizing the LAGER Survey for z ~ 7 Galaxies
• Constraining the reionization history with CMB and spectroscopic observations
• A lack of LAEs within 5Mpc of a luminous quasar in an overdensity at z=6.9: potential evidence of quasar negative feedback at protocluster scales
• CHORUS IV: Mapping the Spatially Inhomogeneous Cosmic Reionization with Subaru HSC
• Eddington accreting Black Holes in the Epoch of Reionization
• The Impact of Cosmic Variance on Inferences of Global Neutral Fraction Derived from Ly$\alpha$ Luminosity Functions During Reionization
• A fast method of reionization parameter space exploration using GPR trained SCRIPT
• Distinguishing reionization models using the largest cluster statistics of the 21-cm maps
• The PAU Survey: Photometric redshift estimation in deep wide fields
• Unlocking Sensitivity for Visibility-based Estimators of the 21 cm Reionization Power Spectrum
• Reconstruction of Reionization History through Dispersion Measure of Fast Radio Bursts
• Constraining the 21cm brightness temperature of the IGM at $z$=6.6 around LAEs with the Murchison Widefield Array
• Lyman alpha Properties of Simulated Galaxies in Overdense Regions: Effects of Galactic Winds at z > 6
• Lyman Alpha line properties at $z\simeq 3.78$ and their environmental dependence: a case study around a massive proto-cluster
• First upper limits on the 21-cm signal power spectrum of neutral hydrogen at $z=9.16$ from the LOFAR 3C196 field
• Impact of the Epoch of Reionization sources on the 21-cm bispectrum
• Interpreting the HI 21-cm cosmology maps through Largest Cluster Statistics -- I: Impact of the synthetic SKA1-Low observations
• Probing Patchy Reionization with the Void Probability Function of Lyman-$\alpha$ Emitters
• Probing the Epoch of Reionization using synergies of line intensity mapping
• Distinguishing AGN from starbursts as the origin of double peaked Lyman-Alpha Emitters in the reionization era
• The Epoch of Reionization in Warm Dark Matter Scenarios
• Scattering of Lyα Photons through the Reionizing Intergalactic Medium: I. Spectral Energy Distribution
• Lyman-$\alpha$ Emitting Galaxies (LAEs) at Cosmic Dawn: Implications and Predictions
• Lyman-α polarization from cosmological ionization fronts: I. Radiative transfer simulations
• From ANN to BNN: Inferring Reionization Parameters using Uncertainty-aware Emulators of 21-cm Summaries
• A Search for Lensed Lyman-Alpha Emitters within the Early HETDEX Data Set
• Deep JWST spectroscopy of galaxies in a candidate ionized bubble at $z=8.7$: probing reionization at pMpc scales with Ly$\alpha$ emission
• The MUSE Hubble Ultra Deep Field Survey XIV. The evolution of the Lya emitter fraction from z=3 to z=6
• Constraints on the Epoch of Reionization with Roman Space Telescope and the Void Probability Function of Lyman-Alpha Emitters
• A resolved Lyman-Alpha profile with doubly peaked emission at z~7
• Can luminous Lyman alpha emitters at $z$ $\simeq$ 5.7 and $z$ $\simeq$ 6.6 suppress star formation?
• A flexible method for estimating luminosity functions via Kernel Density Estimation -- II. Generalization and Python implementation
• CosmoUiT: A Vision Transformer-UNet Hybrid for Fast and Accurate Emulation of 21-cm Maps from the Epoch of Reionization
• Unveiling the most luminous Lyman-α emitters in the epoch of reionisation