Probing High-Redshift Galaxy Formation at the Highest Luminosities: New Insights from DEIMOS Spectroscopy

Abstract

We present DEIMOS spectroscopic observations of the most UV-luminous star-forming galaxies at 3.2<z<4.6. Our sample contains galaxies with luminosities of L*<L<7L* and is one of the largest samples to date of the most UV-luminous galaxies at these redshifts. Our data confirm 41 star-forming galaxies at 3.2<z<4.6 and validate the clean selection of the photometric candidates. We find that the fraction of Lya emitting galaxies increases with decreasing UV luminosity. We find strong evidence of large-scale outflows, transporting the neutral/ionized gas in the interstellar medium away from the galaxy. Galaxies exhibiting both interstellar absorption and Lya emission lines show a significant velocity offset between the two features (200-1140 km/s). We find tentative evidence that this measure of the outflow velocity increases with UV luminosity and/or stellar mass. The luminosity- and mass-dependent outflow strengths suggest that the efficiency of feedback and enrichment of the surrounding medium depend on these parameters. We present composite spectra of the absorption-line-only and Lya-emitting subsets of the UV luminous galaxies at z~3.7. The composite spectra are similar to those of lower-z and lower-luminosity LBGs samples, but with some subtle differences. Analyses of the composite spectra suggest that the UV luminous LBGs at z~3.7 may have a higher covering fraction of absorbing gas, and may be older than their lower-z and lower-luminosity counterparts. In addition, we have discovered 5 galaxies that belong to a massive overdensity at z=3.78. Finally, two galaxies each show two distinct sets of interstellar absorption features. The latter may be a sign of a final stage of major merger, or clumpy disk formation. Their presence implies that frequency of such sources among our luminous z~3.7 LBGs may be an order of magnitude higher than in lower redshift and lower luminosity samples.

19 pages, 12 figures, final version, Accepted for publication in Astrophysical Journal

References in corpus (19)

• Planck 2013 results. XVI. Cosmological parameters
• Astrophysics Source Code Library
• Formation of Massive Galaxies at High Redshift: Cold Streams, Clumpy Disks and Compact Spheroids
• Ubiquitous outflows in DEEP2 spectra of star-forming galaxies at z=1.4
• UV Luminosity Functions at z~4, 5, and 6 from the HUDF and other Deep HST ACS Fields: Evolution and Star Formation History
• 3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies
• Subaru Deep Survey V. A Census of Lyman Break Galaxies at z=4 and 5 in the Subaru Deep Fields: Photometric Properties
• A massive proto-cluster of galaxies at a redshift of z {\approx} 5.3
• The Characteristic Star Formation Histories of Galaxies at Redshifts z~2-7
• The DEEP2 Galaxy Redshift Survey: The Role of Galaxy Environment in the Cosmic Star-Formation History
• The Spitzer Deep, Wide-Field Survey
• The Properties and Prevalence of Galactic Outflows at z = 1 in the Extended Groth Strip
• Mapping Large-Scale Gaseous Outflows in Ultraluminous Infrared Galaxies with Keck II ESI Spectra: Spatial Extent of the Outflow
• Integral Field Spectroscopy of High-Redshift Star Forming Galaxies with Laser Guided Adaptive Optics: Evidence for Dispersion-Dominated Kinematics
• Mapping the Dark Matter From UV Light at High Redshift: An Empirical Approach to Understand Galaxy Statistics
• The physical properties of Lyalpha emitting galaxies: not just primeval galaxies?
• Physical properties of z~4 LBGs: differences between galaxies with and without Ly-alpha emission
• Herschel Detection of Dust Emission from UV-Luminous Star-Forming Galaxies at 3.3<z<4.3
• GaBoDS: The Garching-Bonn Deep Survey VIII. Lyman-break galaxies in the ESO Deep Public Survey

Cited by in corpus (18)

• Photometric redshifts for the next generation of deep radio continuum surveys - I: Template fitting
• Shadow of a Colossus: A z=2.45 Galaxy Protocluster Detected in 3D Ly-a Forest Tomographic Mapping of the COSMOS Field
• The LOFAR Two-metre Sky Survey IV. First Data Release: Photometric redshifts and rest-frame magnitudes
• A First Site of Galaxy Cluster Formation: Complete Spectroscopy of a Protocluster at $z=6.01$
• Discovery of a Very Large Structure at Z=3.78
• Spectroscopic Confirmation of a Protocluster at z=3.786
• Photometric redshifts for the next generation of deep radio continuum surveys - II. Gaussian processes and hybrid estimates
• The UV-brightest Lyman continuum emitting star-forming galaxy
• The Diversity of Diffuse Ly$\alpha$ Nebulae around Star-Forming Galaxies at High Redshift
• The interstellar medium and feedback in the progenitors of the compact passive galaxies at z~2
• A 52 hours VLT/FORS2 spectrum of a bright z~7 HUDF galaxy: no Ly-alpha emission
• A census of galaxy constituents in a Coma Progenitor observed at z>3
• Rest-frame UV Properties of Luminous Strong Gravitationally Lensed Ly$\alpha$ Emitters from the BELLS GALLERY Survey
• The Clustering and Halo Masses of Star Forming Galaxies at z<1
• The LOFAR Two-metre Sky Survey Deep Fields -- Data Release 1: IV. Photometric redshifts and stellar masses
• Discovery of a Very Large (~20 kpc) Galaxy at z=3.72
• A Search for Massive Galaxy Population in a Protocluster of LAEs at $z=2.39$ near the Radio Galaxy 53W002
• The Environment of Lyman Break Analogues (ELBA) survey: Star-forming galaxies in small groups