We present results on the size evolution of passively evolving galaxies at 1 . z . 2 drawn from the Wide Field Camera 3 Early Release Science program. Our sample was constructed using an analog to the passive BzK selection criterion, which isolates galaxies with little or no on-going star formation at z & 1.5. We identify 30 galaxies in 40 arcmin2 to H < 25 mag. We supplement spectroscopic redshifts from the literature with photometric redshifts determined from the 15-band photometry from 0.22 . 8 ƒÊm. We determine effective radii from SLersic profile fits to the H-band image using an empirical PSF. We find that size evolution is a strong function of stellar mass, with the most massive (M 1011 M) galaxies undergoing the most rapid evolution from z 2 to the present. Parameterizing the size evolution as (1 + z)., we find a tentative scaling between and stellar mass of .1.8 + 1.4 log(M/109 M). We briefly discuss the implications of this result for our understanding of the dynamical evolution of the red galaxies.
Ryan, Jr; McCarthy; Cohen; Yan; Hathi; Koekemoer; Rutkowski; Mechtley; Windhorst; O’Connell; Balick; Bond; Bushouse; and Calzetti, D, "THE SIZE EVOLUTION OF PASSIVE GALAXIES: OBSERVATIONS FROM THE WIDE FIELD CAMERA 3 EARLY RELEASE SCIENCE PROGRAM" (2010). Astronomy Department Faculty Publication Series. 953.