The galaxy luminosity - size relation and selection biases in the Hubble Ultra Deep Field
Abstract
Description
We use the Hubble Ultra Deep Field to study the galaxy luminosity-size (M-Re) distribution. With a careful analysis of selection effects due to both detection completeness and measurement reliability we identify bias-free regions in the M-Re 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 surface brightness for galaxies in a sample spanning 8 magnitudes in luminosity between M = -22 and -14 mag increases by ~1.0 mag/arcsec^2 from z ~ 0.1 to z ~ 0.7. We also highlight the importance of considering surface brightness dependent measurement biases in addition to incompleteness biases. In particular, the increasing, systematic under-estimation of Kron fluxes towards low surface brightnesses may cause diffuse, yet luminous, systems to be mistaken for faint, compact objects.
15 pages, 12 figures. Accepted for publication in MNRAS
15 pages, 12 figures. Accepted for publication in MNRAS