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Morphologies of Local Lyman Break Galaxy Analogs. II. A Comparison with Galaxies at z ≃ 2–4 in ACS and WFC3 Images of the Hubble Ultra Deep Field

Overzier, R. A. and Heckman, T. M. and Schiminovich, D. and Basu-Zych, A. and Gonçalves, T. and Martin, D. C. and Rich, R. M. (2010) Morphologies of Local Lyman Break Galaxy Analogs. II. A Comparison with Galaxies at z ≃ 2–4 in ACS and WFC3 Images of the Hubble Ultra Deep Field. Astrophysical Journal, 710 (2). pp. 979-991. ISSN 0004-637X. http://resolver.caltech.edu/CaltechAUTHORS:20100225-165613498

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Abstract

Previous work has shown that Lyman break galaxies (LBGs) display a range in structures (from single and compact to more clumpy and extended) that is different from typical local star-forming galaxies. Recently, we have introduced a sample of rare, nearby (z < 0.3) starburst galaxies that appear to be good analogs of LBGs. These "Lyman break analogs" (LBAs) provide an excellent training set for understanding starbursts at different redshifts. We present an application of this by comparing the rest-frame ultraviolet (UV) and optical morphologies of 30 LBAs with those of galaxies at z ~ 2-4 in the Hubble Ultra Deep Field. We compare LBAs with star-forming sBzK galaxies at z ~ 2, and LBGs at z ~ 3-4 at the same intrinsic UV luminosity (L_(UV) ≳ 0.3L^*_(z=3)). The UV/optical colors and sizes of LBAs and LBGs are very similar, while the BzK galaxies are somewhat redder and larger. LBAs lie along a mass-metallicity relation that is offset from that of typical local galaxies, but similar to that seen at z ~ 2. There is significant overlap between the morphologies (G, C, A, and M_(20)) of the local and high-redshift samples, although the high-redshift samples are somewhat less concentrated and clumpier than the LBAs. Based on their highly asymmetric morphologies, we find that in the majority of LBAs the starbursts appear to be triggered by interactions/mergers. When the images of the LBAs are degraded to the same sensitivity and linear resolution as the images of LBGs and BzK galaxies, we find that these relatively faint asymmetric features are no longer detectable. This effect is particularly severe in the rest-frame UV. It has been suggested that high-redshift galaxies experience intense bursts unlike anything seen in the local universe, possibly due to cold flows and instabilities. In part, this is based on the fact that the majority (~70%) of LBGs do not show morphological signatures of interactions or mergers. Our results suggest that this evidence is insufficient, since a large fraction of such signatures would likely have been missed in current observations of galaxies at z ~ 2-4. This leaves open the possibility that clumpy accretion and mergers remain important in driving the evolution of these starbursts, together with rapid gas accretion through other means.


Item Type:Article
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http://dx.doi.org/10.1088/0004-637X/710/2/979DOIArticle
http://www.iop.org/EJ/abstract/0004-637X/710/2/979/PublisherArticle
Additional Information:© 2010 American Astronomical Society. Print publication: Issue 2 (2010 February 20); received 2009 November 6; accepted for publication 2010 January 6; published 2010 January 25. We are grateful to Xu Kong for providing us with the source list of BzK galaxies in the HUDF from Kong et al. (2008). We thank Guinevere Kauffmann, Qi Guo, and Eyal Neistein for sharing their insight on the different gas accretion modes. We thank Lee Armus, Brant Robertson, James Bullock, Marc Rafelski, and Jeff Cooke for very useful comments to a previous version of this paper submitted to the e-print archive. Based on observations made with the NASA/ESA HST, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 10920, 11107, and 11563.
Group:Space Astrophysics Laboratory
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Funding AgencyGrant Number
NASANAS 5-26555
Subject Keywords:cosmology: observations; early universe; galaxies: high-redshift; galaxies: starburst
Record Number:CaltechAUTHORS:20100225-165613498
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20100225-165613498
Official Citation:Morphologies of Local Lyman Break Galaxy Analogs. II. A Comparison with Galaxies at z 2–4 in ACS and WFC3 Images of the Hubble Ultra Deep Field R. A. Overzier, T. M. Heckman, D. Schiminovich, A. Basu-Zych, T. Gonçalves, D. C. Martin, and R. M. Rich 2010 ApJ 710 979-991 doi: 10.1088/0004-637X/710/2/979
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17602
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:26 Feb 2010 21:14
Last Modified:28 Aug 2016 20:44

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