The Building the Bridge survey for z=3 Ly-alpha emitting galaxies II: Completion of the survey

Abstract

(Abridged). We aim at bridging the gap between absorption selected and emission selected galaxies at z~3 by probing the faint end of the luminosity function of star-forming galaxies at z~3. We have performed narrow-band imaging in three fields with intervening QSO absorbers (a damped Ly$\alpha$ absorber and two Lyman-limit systems) using the VLT. We target Ly-alpha at redshifts 2.85, 3.15 and 3.20. We find a consistent surface density of about 10 Ly-alpha-emitters per square arcmin per unit redshift in all three fields down to our detection limit of about 3x10^41 ergs s^-1. The luminosity function is consistent with what has been found by other surveys at similar redshifts. About 85% of the sources are fainter than the canonical limit of R=25.5 for most Lyman-break galaxy surveys. In none of the three fields do we detect the emission counterparts of the QSO absorbers. In particular we do not detect the counterpart of the z=2.85 damped Ly-alpha absorber towards Q2138-4427. Narrow-band surveys for Ly-alpha emitters are excellent to probe the faint end of the luminosity function at z~3. There is a very high surface density of this class of objects. This is consistent with a very steep slope of the faint end of the luminosity function as has been inferred by other studies. This faint population of galaxies is playing a central role in the early Universe. There is evidence that this population is dominating the integrated star-formation activity, responsible for the bulk of the ionizing photons at z~3 and likely also responsible for the bulk of the enrichment of the intergalactic medium.

15 pages, 13 figures. Accepted for publication in A&A

References in corpus (13)

• 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
• Ly-alpha Emission-Line Galaxies at z = 3.1 in the Extended Chandra Deep Field South
• A galaxy at a redshift z = 6.96
• Velocity-Metallicity Correlation for high-z DLA Galaxies: Evidence for a Mass-Metallicity Relation?
• Evolution of the Intergalactic Opacity: Implications for the Ionizing Background, Cosmic Star Formation, and Quasar Activity
• A Population of Faint Extended Line Emitters and the Host Galaxies of Optically Thick QSO Absorption Systems
• Damped Lyman Alpha Systems in Galaxy Formation Simulations
• Protoclusters associated with z > 2 radio galaxies. I. Characteristics of high redshift protoclusters
• Reconciling the Metallicity Distributions of Gamma-ray Burst, Damped Lyman-alpha, and Lyman-break Galaxies at z=3
• Ly-alpha and UV emission from high-redshift GRB hosts: To what extent do GRBs trace star formation?
• An integral field spectroscopic survey for high redshift damped Lyman-alpha galaxies
• Where are the Cosmic Metals at z~3?
• Tracing large-scale structure at high redshift with Lyman-alpha emitters: the effect of peculiar velocities

Cited by in corpus (9)

• MUSE searches for galaxies near very metal-poor gas clouds at z~3: new constraints for cold accretion models
• MUSE Analysis of Gas around Galaxies (MAGG) -- I: Survey design and the environment of a near pristine gas cloud at z~3.5
• MUSE Analysis of Gas around Galaxies (MAGG) -- IV: The gaseous environment of $z\sim$ 3-4 Lyman-alpha emitting galaxies
• Linking gas and galaxies at high redshift: MUSE surveys the environments of six damped Lyman alpha galaxies at z~3
• Lyman Alpha and MgII as Probes of Galaxies and their Environments
• A survey of Ly$\alpha$ emission around Damped Ly$\alpha$ absorbers at $z\approx 2$ with the Keck Cosmic Web Imager
• Spitzer's View of the Candidate Cluster and Protocluster Catalog (CCPC)
• Identifying Lyα emitter candidates with Random Forest: learning from galaxies in CANDELS survey
• A gradient boosting and broadband approach to finding Lyman-α emitting galaxies beyond narrowband surveys