The galaxy luminosity–size relation and selection biases in the Hubble Ultra Deep Field |
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| Authors: | E Cameron † S P Driver |
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| Institution: | Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611, Australia;Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS |
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| Abstract: | We use the Hubble Ultra Deep Field to study the galaxy luminosity–size ( M – R e ) distribution. With a careful analysis of selection effects due to both detection completeness and measurement reliability, we identify bias-free regions in the M – R e plane for a series of volume-limited samples. By comparison to a nearby survey also having well-defined selection limits, namely the Millennium Galaxy Catalogue, we present clear evidence for evolution in surface brightness since z ～ 0.7 . Specifically, we demonstrate that the mean, rest-frame B -band 〈μ〉 e for galaxies in a sample spanning 8 mag in luminosity between M B =?22 and ?14 mag increases by ～1.0 mag arcsec?2 from z ～ 0.1 to 0.7. We also highlight the importance of considering surface brightness-dependent measurement biases in addition to incompleteness biases. In particular, the increasing, systematic underestimation of Kron fluxes towards low surface brightnesses may cause diffuse, yet luminous, systems to be mistaken for faint, compact objects. |
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| Keywords: | galaxies: evolution galaxies: formation galaxies: high-redshift galaxies: photometry |
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