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Title: STAR FORMATION FROM DLA GAS IN THE OUTSKIRTS OF LYMAN BREAK GALAXIES AT z {approx} 3

Abstract

We present evidence for spatially extended low surface brightness emission around Lyman break galaxies (LBGs) in the V-band image of the Hubble Ultra Deep Field, corresponding to the z {approx} 3 rest-frame far-UV (FUV) light, which is a sensitive measure of star formation rates (SFRs). We find that the covering fraction of molecular gas at z {approx} 3 is not adequate to explain the emission in the outskirts of LBGs, while the covering fraction of neutral atomic-dominated hydrogen gas at high redshift is sufficient. We develop a theoretical framework to connect this emission around LBGs to the expected emission from neutral H I gas, i.e., damped Ly{alpha} systems (DLAs), using the Kennicutt-Schmidt (KS) relation. Working under the hypothesis that the observed FUV emission in the outskirts of LBGs is from in situ star formation in atomic-dominated hydrogen gas, the results suggest that the SFR efficiency in such gas at z {approx} 3 is between factors of 10 and 50 lower than predictions based on the local KS relation. The total SFR density in atomic-dominated gas at z {approx} 3 is constrained to be {approx}10% of that observed from the inner regions of LBGs. In addition, the metals produced by inmore » situ star formation in the outskirts of LBGs yield metallicities comparable to those of DLAs, which is a possible solution to the 'Missing Metals' problem for DLAs. Finally, the atomic-dominated gas in the outskirts of galaxies at both high and low redshifts has similar reduced SFR efficiencies and is consistent with the same power law.« less

Authors:
;  [1];  [2]
  1. Department of Physics and Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA 92093-0424 (United States)
  2. Department of Astronomy and Astrophysics and Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States)
Publication Date:
OSTI Identifier:
21578291
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 736; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/736/1/48; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; EMISSION; GALACTIC EVOLUTION; GALAXIES; HYDROGEN; PHOTOMETRY; RED SHIFT; STARS; ELEMENTS; EVOLUTION; NONMETALS

Citation Formats

Rafelski, Marc, Wolfe, Arthur M., and Chen, Hsiao-Wen, E-mail: marcar@ucsd.edu, E-mail: awolfe@ucsd.edu, E-mail: hchen@oddjob.uchicago.edu. STAR FORMATION FROM DLA GAS IN THE OUTSKIRTS OF LYMAN BREAK GALAXIES AT z {approx} 3. United States: N. p., 2011. Web. doi:10.1088/0004-637X/736/1/48.
Rafelski, Marc, Wolfe, Arthur M., & Chen, Hsiao-Wen, E-mail: marcar@ucsd.edu, E-mail: awolfe@ucsd.edu, E-mail: hchen@oddjob.uchicago.edu. STAR FORMATION FROM DLA GAS IN THE OUTSKIRTS OF LYMAN BREAK GALAXIES AT z {approx} 3. United States. doi:10.1088/0004-637X/736/1/48.
Rafelski, Marc, Wolfe, Arthur M., and Chen, Hsiao-Wen, E-mail: marcar@ucsd.edu, E-mail: awolfe@ucsd.edu, E-mail: hchen@oddjob.uchicago.edu. Wed . "STAR FORMATION FROM DLA GAS IN THE OUTSKIRTS OF LYMAN BREAK GALAXIES AT z {approx} 3". United States. doi:10.1088/0004-637X/736/1/48.
@article{osti_21578291,
title = {STAR FORMATION FROM DLA GAS IN THE OUTSKIRTS OF LYMAN BREAK GALAXIES AT z {approx} 3},
author = {Rafelski, Marc and Wolfe, Arthur M. and Chen, Hsiao-Wen, E-mail: marcar@ucsd.edu, E-mail: awolfe@ucsd.edu, E-mail: hchen@oddjob.uchicago.edu},
abstractNote = {We present evidence for spatially extended low surface brightness emission around Lyman break galaxies (LBGs) in the V-band image of the Hubble Ultra Deep Field, corresponding to the z {approx} 3 rest-frame far-UV (FUV) light, which is a sensitive measure of star formation rates (SFRs). We find that the covering fraction of molecular gas at z {approx} 3 is not adequate to explain the emission in the outskirts of LBGs, while the covering fraction of neutral atomic-dominated hydrogen gas at high redshift is sufficient. We develop a theoretical framework to connect this emission around LBGs to the expected emission from neutral H I gas, i.e., damped Ly{alpha} systems (DLAs), using the Kennicutt-Schmidt (KS) relation. Working under the hypothesis that the observed FUV emission in the outskirts of LBGs is from in situ star formation in atomic-dominated hydrogen gas, the results suggest that the SFR efficiency in such gas at z {approx} 3 is between factors of 10 and 50 lower than predictions based on the local KS relation. The total SFR density in atomic-dominated gas at z {approx} 3 is constrained to be {approx}10% of that observed from the inner regions of LBGs. In addition, the metals produced by in situ star formation in the outskirts of LBGs yield metallicities comparable to those of DLAs, which is a possible solution to the 'Missing Metals' problem for DLAs. Finally, the atomic-dominated gas in the outskirts of galaxies at both high and low redshifts has similar reduced SFR efficiencies and is consistent with the same power law.},
doi = {10.1088/0004-637X/736/1/48},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 736,
place = {United States},
year = {2011},
month = {7}
}