Department of Astronomy & Physics

PHD THESIS DEFENCE TALK: Massive Passive Galaxies at z~1.6

Speaker: Liz Arcila-Osejo (Saint Mary's University)
Time: March 29, 2018 - 9:00 AM
Location: Loyola 273


We present a K-selected catalog of z ~ 1.6 gzKs galaxies in the Deep and Wide fields of the Canada-France-Hawaii Legacy Survey, with a final effective area of 27.6 deg2  allowing  us  to recover a representative sample of rare massive passive galaxies (log (M*/M) > 11.14) and very rare ultra-massive passive galaxies (log (M*/M) > 11.49). The latter is an important population of galaxies, with significant build-up of stellar mass when the universe was only ~ 4 Gyr old. 
This catalog allows us to constrain the bright end of the stellar mass function. Once corrected for Eddington bias, we find the number density of passive galaxies at z~1.6 to be well described by a Schechter function. Next, we find an absence of massive companions around ultra-massive passive galaxies (UMPEGs) and only a handful of lower mass companions. Based on a simple dynamical friction estimate, we calculate these UMPEGs to grow ~25% between z~1.6 and z~1. Finally,  we recover regions with an over-density of massive passive galaxies as sample environments for proto-clusters with an evolved population.


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