Lyman Break Galaxies at z~5: Rest-Frame UV Spectra. III

Abstract

We present results of optical spectroscopic observations of candidates of Lyman Break Galaxies (LBGs) at $z\sim 5$ in the region including the GOODS-N and the J0053+1234 region by using GMOS-N and GMOS-S, respectively. Among 25 candidates, five objects are identified to be at $z\sim 5$ (two of them were already identified by an earlier study) and one object very close to the color-selection window turned out to be a foreground galaxy. With this spectroscopically identified sample and those from previous studies, we derived the lower limits on the number density of bright ($M_{UV}<-22.0$ mag) LBGs at $z\sim 5$. These lower limits are comparable to or slightly smaller than the number densities of UV luminosity functions (UVLFs) that show the smaller number density among $z\sim 5$ UVLFs in literature. However, by considering that there remain many LBG candidates without spectroscopic observations, the number density of bright LBGs is expected to increase by a factor of two or more. The evidence for the deficiency of UV luminous LBGs with large Ly$\alpha$ equivalent widths was reinforced. We discuss possible causes for the deficiency and prefer the interpretation of dust absorption.

28 pages, 5 figures, accepted for publication in ApJ

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Cited by in corpus (3)

• Radiative Transfer Modeling of Lyman Alpha Emitters. I. Statistics of Spectra and Luminosity
• Stellar Populations of Lyman-alpha Emitters at z=4.86: A Comparison to $z\sim 5$ LBGs
• Spitzer's View of the Candidate Cluster and Protocluster Catalog (CCPC)