The VIMOS Ultra-Deep Survey (VUDS): fast increase of the fraction of strong Lyman alpha emitters from z=2 to z=6

Abstract

Aims. The aim of this work is to constrain the evolution of the fraction of Lya emitters among UV selected star forming galaxies at 2<z<6, and to measure the stellar escape fraction of Lya photons over the same redshift range. Methods. We exploit the ultradeep spectroscopic observations collected by the VIMOS Ultra Deep Survey (VUDS) to build an unique, complete and unbiased sample of 4000 spectroscopically confirmed star forming galaxies at 2<z<6. Our galaxy sample UV luminosities brighter than M* at 2<z<6, and luminosities down to one magnitude fainter than M* at 2<z<3.5. Results. We find that 80% of the star forming galaxies in our sample have EW0(Lya)<10A, and correspondingly fesc(Lya)<1%. By comparing these results with literature, we conclude that the bulk of the Lya luminosity at 2<z<6 comes from galaxies that are fainter in the UV than those we sample in this work. The strong Lya emitters constitute, at each redshift, the tail of the distribution of the galaxies with extreme EW0(Lya) and fesc(Lya) . This tail of large EW0 and fesc(Lya) becomes more important as the redshift increases, and causes the fraction of Lya with EW0> 25A to increase from 5% at z=2 to 30% at z=6, with the increase being relatively stronger beyond z=4. We observe no difference, for the narrow range of UV luminosities explored in this work, between the fraction of strong Lya emitters among galaxies fainter or brighter than M*, although the fraction for the FUV faint galaxies evolves faster, at 2<z<3.5, than for the bright ones. We do observe an anticorrelation between E(B-V) and fesc(Lya): generally galaxies with high fesc(Lya) have also small amounts of dust (and viceversa). However, when the dust content is low (E(B-V)<0.05) we observe a very broad range of fesc(Lya), ranging from 10^-3 to 1. This implies that the dust alone is not the only regulator of the amount of escaping Lya photons.

12 pages, 6 figures, A&A in press

References in corpus (15)

• The Cosmic Evolution Survey (COSMOS) -- Overview
• zCOSMOS: A Large VLT/VIMOS redshift survey covering 0 < z < 3 in the COSMOS field
• UltraVISTA: a new ultra-deep near-infrared survey in COSMOS
• UV Luminosity Functions at z~4, 5, and 6 from the HUDF and other Deep HST ACS Fields: Evolution and Star Formation History
• 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
• 3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies
• The Cosmic Evolution Survey (COSMOS): Subaru Observations of the HST COSMOS Field
• Ly-alpha Emission-Line Galaxies at z = 3.1 in the Extended Chandra Deep Field South
• The Multiwavelength Survey by Yale-Chile (MUSYC): Deep Medium-Band optical imaging and high quality 32-band photometric redshifts in the ECDF-S
• A Spectroscopic Survey of Redshift 1.4<z<3.0 Galaxies in the Goods-North Field: Survey Description, Catalogs, and Properties
• 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)
• Diffuse Lyman-alpha Halos around Galaxies at z=2.2-6.6: Implications for Galaxy Formation and Cosmic Reionization
• Lyman Alpha Emitters at Redshift 5.7 in the COSMOS Field
• Deficiency of large equivalent width Lyman-alpha emission in luminous Lyman break galaxies at z~5-6?
• Lyman alpha emitting galaxies at 0.2 < z < 0.35 from GALEX spectroscopy

Cited by in corpus (51)

• The VIMOS Ultra-Deep Survey: ~10,000 galaxies with spectroscopic redshifts to study galaxy assembly at early epochs 2<z<~6
• Inferences on the Timeline of Reionization at z~8 From the KMOS Lens-Amplified Spectroscopic Survey
• Observations of the Lyman-$\alpha$ Universe
• Identification of the brightest Lyα emitters at z=6.6: implications for the evolution of the luminosity function in the re-ionisation era
• Texas Spectroscopic Search for Ly$\alpha$ Emission at the End of Reionization III. the Ly$\alpha$ Equivalent-width Distribution and Ionized Structures at $z>7$
• A VLT/FORS2 view at $z\sim 6$: Lyman-$\alpha$ emitter fraction and galaxy physical properties at the edge of the epoch of cosmic reionization
• Spectroscopic properties of luminous Lyman-α emitters at $z\approx 6-7$ and comparison to the Lyman-break population
• ZFIRE: A KECK/MOSFIRE Spectroscopic Survey of Galaxies in Rich Environments at z~2
• The MUSE Hubble Ultra Deep Field Survey X. Ly$\alpha$ Equivalent Widths at $2.9<z<6.6$
• The X-SHOOTER Lyman-$\alpha$ survey at z=2 (XLS-z2) I: What makes a galaxy a Lyman-$\alpha$ emitter?
• Chasing passive galaxies in the early Universe: a critical analysis in CANDELS GOODS-South
• The VIMOS Ultra Deep Survey: The reversal of the star-formation rate $-$ density relation at $2<z<5$
• A Comprehensive Study of Ly$\alpha$ Emission in the High-redshift Galaxy Population
• Confirmation of a Steep Luminosity Function for Lyman-alpha Emitters at z = 5.7: A Major Component of Reionization
• The UV, Lyman-alpha, and dark matter halo properties of high redshift galaxies
• The ALMA REBELS Survey: Efficient Ly$\alpha$ Transmission of UV-Bright z$\simeq$7 Galaxies from Large Velocity Offsets and Broad Line Widths
• The evolution of rest-frame UV properties, Lya EWs and the SFR-Stellar mass relation at z~2-6 for SC4K LAEs
• Spectral shapes of the Lyman-alpha emission from galaxies: I. blueshifted emission and intrinsic invariance with redshift
• The ALPINE-ALMA [CII] survey: Small Lya-[CII] velocity offsets in main-sequence galaxies at 4.4 < z < 6
• The MUSE-Wide survey: A measurement of the Ly$\alpha$ emitting fraction among $z>3$ galaxies
• Constraining Lyman-alpha spatial offsets at $3<z<5.5$ from VANDELS slit spectroscopy
• Connecting Faint End Slopes of the Lyman-$\alpha$ emitter and Lyman-break Galaxy Luminosity Functions
• On the sizes of ionized bubbles around the highest redshift galaxies. Spectral shapes of the Lyman-alpha emission from galaxies
• The MUSE Hubble Ultra Deep Field Survey. XV. The mean rest-UV spectra of Ly-alpha emitters at z>3
• Crucial Factors for Lyα Transmission in the Reionizing Intergalactic Medium: Infall Motion, HII Bubble Size, and Self-shielded Systems
• J-PLUS: Unveiling the brightest-end of the Lyα luminosity function at 2.0<z<3.3 over 1000 deg^2
• Ly$\alpha$ Emitters with Very Large Ly$\alpha$ Equivalent Widths, EW${}_0$(Ly$\alpha$) $\simeq 200-400$ Å, at $z\sim 2$
• 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
• CLEAR: Boosted Ly$\alpha$ Transmission of the Intergalactic Medium in UV bright Galaxies
• Rest-frame UV Properties of Luminous Strong Gravitationally Lensed Ly$\alpha$ Emitters from the BELLS GALLERY Survey
• Differences and similarities of stellar populations in LAEs and LBGs at $z\sim$ 3.4 - 6.8
• Simulating JWST/NIRCam Color Selection of High-Redshift Galaxies
• Outside the Lyman-break box: detecting Lyman continuum emitters at $3.5<z<5.1$ with CLAUDS
• The Size and Pervasiveness of Ly$\alpha$-UV Spatial Offsets in Star-Forming Galaxies at $z\sim 6$
• Upper limits on the escape fraction of ionizing radiation from galaxies at $2\lesssim z<6$
• Early Results from GLASS-JWST XXIII: The transmission of Lyman-alpha from UV-faint z ~ 3-6 galaxies
• The evolution of the UV luminosity and stellar mass functions of Lyman-alpha emitters from z~2 to z~6
• Discovering Large-Scale Structure at $2<z<5$ in the C3VO Survey
• CHORUS IV: Mapping the Spatially Inhomogeneous Cosmic Reionization with Subaru HSC
• Evolution of the Lyman-α emitting fraction and UV properties of lensed star-forming galaxies between 2.9 < z < 6.7
• A survey of Ly$\alpha$ emission around Damped Ly$\alpha$ absorbers at $z\approx 2$ with the Keck Cosmic Web Imager
• Photometric IGM Tomography: Efficiently Mapping Quasar Light Echoes with Deep Narrow Band Imaging
• Identifying Lyα emitter candidates with Random Forest: learning from galaxies in CANDELS survey
• Photometric IGM tomography with Subaru/HSC: the large-scale structure of Ly$\alpha$ emitters and IGM transmission in the COSMOS field at $z\sim 5$
• The miniJPAS & J-NEP surveys: Identification and characterization of the Ly$\alpha$ Emitter population and the Ly$\alpha$ Luminosity Function
• Analogs of primeval galaxies two billion years after the Big Bang
• Ly$\alpha$ Emission from [OIII] Emitters Near Reionization: The role of environment in galaxy Ly$\alpha$ detection
• A Ly-alpha nebula at z~3.3
• The MUSE Hubble Ultra Deep Field Survey XIV. The evolution of the Lya emitter fraction from z=3 to z=6
• Probing the influence of the protocluster environment on galaxy morphology at z = 2.23
• A gradient boosting and broadband approach to finding Lyman-α emitting galaxies beyond narrowband surveys