Spectroscopy of z~5 Lyman Break Galaxies in the ESO Remote Galaxy Survey

Abstract

(ABRIDGED) We present the global results of a large spectroscopic survey carried out in order to identify z~ 5 Lyman break galaxies (LBGs) across ten widely-separated fields to I_{AB}=26.3. The redshifts of seventy 4.6<z<5.6 LBGs were identified. We find no significant difference in the frequency of high equivalent-width line emitters between z~3 and our z~5 samples. The rest-frame UV continuum slope of a typical z~5 line-emitting galaxy is bluer than that of a typical break-only galaxy, a difference that is difficult to explain purely by differences in the ages of their stellar populations. Variation in metallicity and/or dust extinction can more straightforwardly account for this difference. Given their UV-continuum slopes, the typical z~5 LBGs have metallicities a factor of three lower than those of LBGs at z~3. HST imaging indicates that a large majority of the spectroscopically-confirmed LBGs in our sample are members of multiple systems and/or show disturbed morphology. Using local LBG analogues as a model, this multiplicity could be explained either by super-starburst regions within a larger unseen structure, or by a high incidence of merging events at this epoch. The current data cannot distinguish between these two possibilities. The surface density of z~5 LBGs in two fields is considerably higher than in the rest. Both show clear spikes in their redshift distributions indicating strong three-dimensional clustering. Neither structure can be bound given their depth in redshift and probably extend beyond the observed fields. The three-dimensional distances between LBGs in the structures are too large for them to have triggered their starbursts through mutual gravitational interaction, and so it is likely that the short-lived LBGs represent only a small fraction of the baryons in the structures.

19 pages, MNRAS in press

References in corpus (19)

• UV Luminosity Functions at z~4, 5, and 6 from the HUDF and other Deep HST ACS Fields: Evolution and Star Formation History
• The Stellar, Gas and Dynamical Masses of Star-Forming Galaxies at z~2
• The star formation histories of galaxies in the Sloan Digital Sky Survey
• HST morphologies of local Lyman break galaxy analogs I: Evidence for starbursts triggered by merging
• The Stellar Masses and Star Formation Histories of Galaxies at z ~ 6: Constraints from Spitzer Observations in the Great Observatories Origins Deep Survey
• A Luminosity Function of Lyman Alpha Emitting Galaxies at Redshift 4.5
• On the Detectability of Lyman-alpha Emission in Star-forming Galaxies: The Role of Dust
• Lyman-break galaxies at z~5 -I. First significant stellar mass assembly in galaxies that are not simply z~3 LBGs at higher redshift
• The escape of Lyman photons from a young starburst: the case of Haro 11
• Physical properties of z~4 LBGs: differences between galaxies with and without Ly-alpha emission
• The GLARE Survey II. Faint z=6 Ly-alpha Line Emitters in the HUDF
• An OSIRIS study of the gas kinematics in a sample of UV-selected galaxies: Evidence of "Hot and Bothered" starbursts in the local Universe
• Lyman Break Galaxies Under a Microscope: The Small Scale Dynamics and Mass of an Arc in the Cluster 1E0657-56
• On Contamination and Completeness in z>5 Lyman Break Galaxy Surveys
• Integral-field spectroscopy of a Lyman-Break Galaxy at z=3.2: evidence for merging
• Discovery of a single faint AGN in a large sample of z>5 Lyman break galaxies
• M-Dwarfs at Large Heliocentric Distances
• Large Scale Structure traced by Molecular Gas at High Redshift
• Studying Large and Small Scale Environments of Ultraviolet Luminous Galaxies

Cited by in corpus (28)

• Pre-Supernova Evolution of Massive Single and Binary Stars
• Spectroscopic Confirmation of Three z-Dropout Galaxies at z = 6.844 - 7.213: Demographics of Lyman-Alpha Emission in z ~ 7 Galaxies
• Stellar Population Effects on the Inferred Photon Density at Reionization
• The VLT-FLAMES Tarantula Survey I: Introduction and observational overview
• Keck Spectroscopy of Faint 3<z<7 Lyman Break Galaxies:- II. A High Fraction of Line Emitters at Redshift Six
• Spectroscopic confirmation of two Lyman break galaxies at redshift beyond 7
• Properties of $z\sim 3-6$ Lyman Break Galaxies. II. Impact of nebular emission at high redshift
• The effect of stellar evolution uncertainties on the rest-frame ultraviolet stellar lines of CIV and HeII in high-redshift Lyman-break galaxies
• Spectroscopic confirmation of a galaxy at redshift z=8.6
• The size-luminosity relation at z=7 in CANDELS and its implication on reionization
• Are z~5 QSOs found in the most massive high redshift over-densities?
• Hubble Tarantula Treasury Project: Unraveling Tarantula's Web. I. Observational overview and first results
• Mapping Luminous Hot Stars in the Galaxy
• On Lya emission in z~3-6 UV-selected galaxies
• High-redshift galaxies and low-mass stars
• Exploring dust extinction at the edge of reionization
• Detections of Faint Lyman-alpha Emitters at z = 5.7: Galaxy Building Blocks and Engines of Reionization
• SCUBA-2 observations of candidate starbursting protoclusters selected by Planck and Herschel-SPIRE
• The detection of FIR emission from high redshift star-forming galaxies in the ECDF-S
• Physical Properties of Local Star-Forming Analogues to z~5 Lyman Break Galaxies
• Establishing an analogue population for the most distant galaxies
• IR characteristic emission and dust properties of star-forming galaxies at 4.5 $<$ z $<$ 6.2
• The nature and descendants of Lyman-break galaxies in the LambdaCDM cosmology
• Limits on dust emission from z~5 LBGs and their local environments
• Applications of Stellar Population Synthesis in the Distant Universe
• SCUBA-2 overdensities associated with candidate protoclusters selected from Planck data
• Detecting Massive Galaxies at High Redshift using the Dark Energy Survey
• Cl 1103.7-1245 at z=0.96: the highest redshift galaxy cluster in the EDisCS survey