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Evolution of the Sizes of Galaxies over 7 < z < 12 Revealed by the 2012 Hubble Ultra Deep Field Campaign

Ono, Yoshiaki and Ouchi, Masami and Curtis-Lake, Emma and Schenker, Matthew A. and Ellis, Richard S. and McLure, Ross J. and Dunlop, James S. and Robertson, Brant E. and Koekemoer, Anton M. and Bowler, Rebecca A. A. and Rogers, Alexander B. and Schneider, Evan and Charlot, Stéphane and Stark, Daniel P. and Shimasaku, Kazuhiro and Furlanetto, Steven R. and Cirasuolo, Michele (2013) Evolution of the Sizes of Galaxies over 7 < z < 12 Revealed by the 2012 Hubble Ultra Deep Field Campaign. Astrophysical Journal, 777 (2). Art. No. 155. ISSN 0004-637X. doi:10.1088/0004-637X/777/2/155.

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We analyze the redshift- and luminosity-dependent sizes of dropout galaxy candidates in the redshift range z ~ 7-12 using deep images from the 2012 Hubble Ultra Deep Field (UDF12) campaign, which offers two advantages over that used in earlier work. First, we utilize the increased signal-to-noise ratio offered by the UDF12 imaging to provide improved measurements for known galaxies at z ≃ 6.5-8 in the HUDF. Second, because the UDF12 data have allowed the construction of the first robust galaxy sample in the HUDF at z > 8, we have been able to extend the measurement of average galaxy size out to higher redshifts. Restricting our measurements to sources detected at >15σ, we confirm earlier indications that the average half-light radii of z ~ 7-12 galaxies are extremely small, 0.3-0.4 kpc, comparable to the sizes of giant molecular associations in local star-forming galaxies. We also confirm that there is a clear trend of decreasing half-light radius with increasing redshift, and provide the first evidence that this trend continues beyond z ≃ 8. Modeling the evolution of the average half-light radius as a power law, ∝(1 + z)^s , we obtain a best-fit index of s = -1.30^(+0.12)_(-0.14) over z ~ 4-12. A clear size-luminosity relation is evident in our dropout samples. This relation can be interpreted in terms of a constant surface density of star formation over a range in luminosity of 0.05-1.0L^*_(z=3). The average star formation surface density in dropout galaxies is 2-3 orders of magnitude lower than that found in extreme starburst galaxies, but is comparable to that seen today in the centers of normal disk galaxies.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ouchi, Masami0000-0002-1049-6658
Ellis, Richard S.0000-0001-7782-7071
Robertson, Brant E.0000-0002-4271-0364
Koekemoer, Anton M.0000-0002-6610-2048
Furlanetto, Steven R.0000-0002-0658-1243
Additional Information:© 2013 American Astronomical Society. Received 2012 December 13; accepted 2013 September 27; published 2013 October 24. We thank the anonymous referee for constructive comments and suggestions. We also thank Rieko Momose and Suraphong Yuma for their helpful comments. This work was supported by Japan Society for the Promotion of Science (JSPS), Grants-in-Aid for Scientific Research (KAKENHI), Grant Numbers 24840010 and 23244025, and World Premier International Research Center Initiative (WPI Initiative),MEXT, Japan. E.F.C.L., A.B.R., and M.C. acknowledge the support of the UK Science and Technology Facilities Council. The U.S. authors acknowledge financial support from the Space Telescope Science Institute under award HST-GO-12498.01-A. J.S.D. and R.A.A.B. acknowledge the support of the European Research Council via the award of an Advanced Grant to J.S.D. J.S.D. also acknowledges the support of the Royal Society through a Wolfson Research Merit Award. S.C. acknowledges the support of the European Commission through the Marie Curie Initial Training Network ELIXIR. This work is based on data from the Hubble Space Telescope which is operated by NASA through the Space Telescope Science Institute via the association of Universities for Research in Astronomy, Inc., for NASA under contract NAS5-26555.
Funding AgencyGrant Number
Japan Society for the Promotion of Science (JSPS)24840010
Japan Society for the Promotion of Science (JSPS)23244025
Ministry of Education, Culture, Sports, Science and Technology (MEXT)UNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
European Research Council (ERC)UNSPECIFIED
Marie Curie FellowshipUNSPECIFIED
Subject Keywords: galaxies: evolution; galaxies: formation; galaxies: high-redshift; galaxies: structure
Issue or Number:2
Record Number:CaltechAUTHORS:20131202-135305186
Persistent URL:
Official Citation: Evolution of the Sizes of Galaxies over 7 < z < 12 Revealed by the 2012 Hubble Ultra Deep Field Campaign Yoshiaki Ono et al. 2013 ApJ 777 155
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42776
Deposited By: Ruth Sustaita
Deposited On:02 Dec 2013 22:35
Last Modified:10 Nov 2021 16:28

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