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The ERO Host Galaxy of GRB 020127: Implications for the Metallicity of GRB Progenitors

Berger, E. and Fox, D. B. and Kulkarni, S. R. and Frail, D. A. and Djorgovski, S. G. (2007) The ERO Host Galaxy of GRB 020127: Implications for the Metallicity of GRB Progenitors. Astrophysical Journal, 660 (1). pp. 504-508. ISSN 0004-637X. doi:10.1086/513007.

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We present optical and near-IR observations of the host galaxy of GRB 020127, for which we measure R - K_s = 6.2 mag. This is only the second GRB host to date classified as an ERO. The spectral energy distribution (SED) is typical of a dusty starburst galaxy, with a redshift z ≈ 1.9, a luminosity L ≈ 5L^*, and an inferred stellar mass of M_* ~ 10^(11)-10^(12) M_⊙, two orders of magnitude more massive than typical GRB hosts. A comparison to the z ~ 2 mass-metallicity (M-Z) relation suggests that the host metallicity is about 0.5-1Z_⊙. This result shows that at least some GRBs occur in massive, metal-enriched galaxies, and that the proposed low-metallicity bias of GRB progenitors is not as severe as previously claimed. Instead, we propose that the blue colors and sub-L^* luminosities of most GRB hosts reflect their young starburst populations. This explanation also accounts for the prevalence of low-redshift GRBs in low-mass galaxies, since star formation activity shifts from high- to low-mass galaxies as a function of decreasing redshift ("downsizing"). Thus, the low-metallicity bias claimed for z ≾ 0.2 GRB hosts is likely a secondary effect, which reflects the M-Z relation, and consequently GRBs and their hosts may serve as a reliable tracer of cosmic star formation activity.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
Berger, E.0000-0002-9392-9681
Fox, D. B.0000-0002-3714-672X
Kulkarni, S. R.0000-0001-5390-8563
Djorgovski, S. G.0000-0002-0603-3087
Additional Information:© 2007 The American Astronomical Society. Received 2006 September 5; accepted 2007 January 21. We thank J. Kollmeier, D. Erb, and the anonymous referee for helpful comments on the manuscript. E. B. is supported by NASA through Hubble Fellowship grant HST-01171.01 awarded by STScI, which is operated by AURA, Inc. for NASA under contract NAS5-26555. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.
Funding AgencyGrant Number
NASA Hubble FellowshipHST-01171.01
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:galaxies: starburst; gamma rays: bursts
Issue or Number:1
Record Number:CaltechAUTHORS:20091019-104150426
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Official Citation:The ERO Host Galaxy of GRB 020127: Implications for the Metallicity of GRB Progenitors E. Berger, D. B. Fox, S. R. Kulkarni, D. A. Frail, and S. G. Djorgovski 2007 ApJ 660 504-508 doi: 10.1086/513007
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16380
Deposited By: Tony Diaz
Deposited On:26 Oct 2009 18:18
Last Modified:08 Nov 2021 23:26

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