Evolution of the observed Ly-alpha luminosity function from z = 6.5 to z = 7.7: evidence for the epoch of reionization ?

Abstract

Aims. Ly-alpha emitters (LAEs) can be detected out to very high redshifts during the epoch of reionization. The evolution of the LAE luminosity function with redshift is a direct probe of the Ly-alpha transmission of the intergalactic medium (IGM), and therefore of the IGM neutral-hydrogen fraction. Measuring the Ly-alpha luminosity function (LF) of LAEs at redshift z = 7.7 therefore allows us to constrain the ionizing state of the Universe at this redshift. Methods. We observed three 7.5'x7.5' fields with the HAWK-I instrument at the VLT with a narrow band filter centred at 1.06 $\mu$m and targeting LAEs at redshift z ~ 7.7. The fields were chosen for the availability of multiwavelength data. One field is a galaxy cluster, the Bullet Cluster, which allowed us to use gravitational amplification to probe luminosities that are fainter than in the field. The two other fields are subareas of the GOODS Chandra Deep Field South and CFHTLS-D4 deep field. We selected z=7.7 LAE candidates from a variety of colour criteria, in particular from the absence of detection in the optical bands. Results. We do not find any LAE candidates at z = 7.7 in ~2.4 x 10^4 Mpc^3 down to a narrow band AB magnitude of ~ 26, which allows us to infer robust constraints on the Ly-alpha LAE luminosity function at this redshift. Conclusions. The predicted mean number of objects at z = 6.5, derived from somewhat different LFs of Hu et al. (2010), Ouchi et al. (2010), and Kashikawa et al. (2011) are 2.5, 13.7, and 11.6, respectively. Depending on which of these LFs we refer to, we exclude a scenario with no evolution from z = 6.5 to z = 7.7 at 85% confidence without requiring a strong change in the IGM Ly-alpha transmission, or at 99% confidence with a significant quenching of the IGM Ly-alpha transmission, possibly from a strong increase in the high neutral-hydrogen fraction between these two redshifts.

14 pages, 6 figures, accepted for publication in A&A. Added references, minor changes applied in text and figures after the first referee report

References in corpus (15)

• A direct empirical proof of the existence of dark matter
• Observational constraints on Cosmic Reionization
• 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 End of the Reionization Epoch Probed by Ly-alpha Emitters at z=6.5 in the Subaru Deep Field
• The GOODS-MUSIC sample: a multicolour catalog of near-IR selected galaxies in the GOODS-South field
• Strong and weak lensing united III: Measuring the mass distribution of the merging galaxy cluster 1E0657-56
• A galaxy at a redshift z = 6.96
• Completing the Census of Ly-alpha Emitters at the Reionization Epoch
• A Hubble & Spitzer Space Telescope Survey for Gravitationally-Lensed Galaxies: Further Evidence for a Significant Population of Low Luminosity Galaxies beyond Redshift Seven
• Lyman Alpha Emitters in the Hierarchically Clustering Galaxy Formation
• ZEN2: A narrow J-band search for z~9 Lya emitting galaxies directed towards three lensing clusters
• Searching for z~7.7 Lyman Alpha Emitters in the COSMOS Field with NEWFIRM
• The galaxy counts-in-cells distribution from the SDSS
• Narrow-band surveys for very high redshift Lyman-alpha emitters
• A Multiply Imaged Luminous Infrared Galaxy Behind the Bullet Cluster

Cited by in corpus (44)

• Improved upper limits on the 21-cm signal power spectrum of neutral hydrogen at $\mathbf{z}\approx 9.1$ from LOFAR
• Spectroscopic confirmation of z~7 LBGs: probing the earliest galaxies and the epoch of reionization
• New observations of z~7 galaxies: evidence for a patchy reionization
• The Grism Lens-Amplified Survey from Space (GLASS). I. Survey overview and first data release
• 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 $\text{z}=7.3$
• Green Pea Galaxies Reveal Secrets of Ly$\alpha$ Escape
• Evolution in the Escape Fraction of Ionizing Photons and the Decline in Strong Lya Emission from z>6 Galaxies
• The Evolution of the Lyman-Alpha Luminosity Function During Reionization
• Physical Properties of Spectroscopically-Confirmed Galaxies at z >= 6. I. Basic Characteristics of the Rest-Frame UV Continuum and Lyman-alpha emission
• An Empirical Study of the Relationship between Lyα and UV selected Galaxies: Do Theorists and Observers `Select' the Same Objects?
• Spectroscopic observation of Ly$\alpha$ emitters at z~7.7 and implications on re-ionization
• 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
• A 10 deg${}^2$ Lyman-$\alpha$ survey at z=8.8 with spectroscopic follow-up: strong constraints on the LF and implications for other surveys
• Spitzer UltRa Faint SUrvey Program (SURFS UP) I: An Overview
• Searching for z~7.7 Lyman Alpha Emitters in the COSMOS Field with NEWFIRM
• Observing the first galaxies
• Faint end of the $z\sim 3-7$ luminosity function of Lyman-alpha emitters behind lensing clusters observed with MUSE
• 21cmEMU: an emulator of 21cmFAST summary observables
• J-PLUS: Unveiling the brightest-end of the Lyα luminosity function at 2.0<z<3.3 over 1000 deg^2
• Effect of Intergalactic Medium on the Observability of Lyman Alpha Emitters during Cosmic Reionization
• Lyman alpha Luminosity Functions at Redshift z = 4.5
• Constraining the nature of the most distant Gamma-Ray Burst host galaxies
• Spectroscopic Confirmation of a z=6.740 Galaxy behind the Bullet Cluster
• Deep rest-frame far-UV spectroscopy of the giant Lyman-alpha emitter 'Himiko'
• Large-scale environment of z~5.7 CIV absorption systems I: projected distribution of galaxies
• On-sky characterisation of the VISTA NB118 narrow-band filters at 1.19 micron
• What do observations of the Lyman-alpha fraction tell us about reionization?
• Statistical analysis of the causes of excess variance in the 21 cm signal power spectra obtained with the Low-Frequency Array
• Measuring the Stellar Masses of z~7 Galaxies with Spitzer Ultrafaint Survey Program (SURFS UP)
• A Lyman Break Galaxy in the Epoch of Reionization from HST Grism Spectroscopy
• Deep LBT/LUCI Spectroscopy of a Lyman-alpha Emitter Candidate at z ~ 7.7
• A Search for z=7.3 Lyα Emitters behind Gravitationally Lensing Clusters
• Emission line selected galaxies at $z=0.6-2$ in GOODS South: Stellar masses, SFRs, and large scale structure
• Constraining Reionization with Lyman Alpha Emitting Galaxies
• Narrow band selected high redshift galaxy candidates contaminated by lower redshift O[III] ultrastrong emitter line galaxies
• Subaru FOCAS survey of z=7-7.1 Lyα emitters: a test for z >~ 7 Lyα photometric luminosity functions
• A z ~ 5.7 Lyα Emission Line with an Ultra Broad Red Wing
• The miniJPAS & J-NEP surveys: Identification and characterization of the Ly$\alpha$ Emitter population and the Ly$\alpha$ Luminosity Function
• Properties of galaxies at the faint end of the H$\alpha$ luminosity function at $z\sim 0.62$
• Observing the Epoch of Reionization with the Cosmic Microwave Background
• The EAGLE instrument for the E-ELT: developments since delivery of Phase A
• CFHQSIR: a Y-band extension of the CFHTLS-Wide survey
• Simulation based inference of the ionization history from the 2D 21 cm power spectrum