Modelling the properties of high mass galaxies at high redshift

Abstract

A set of galaxies observed at high redshift were modelled to investigate the star formation history and other properties of these galaxies. By the gzK Selection Technique, twelve galaxies from the Canada-France-Hawaii Telescope Legacy survey were selected from the region of gzK colour-colour space that categorizes quiescent galaxies. Using observed magnitudes in the u, g, r, i, z, J, H, K fllters, the galaxies were fit to spectral models using the software SEDfit. From comparison of x2 values between best fitting quiescent/star forming models, the passive quiescent galaxy model was found to best represent the set of galaxies. This best fit quiescent model has galaxies properties of approximately: galaxy masses on the scale of 5 x 10(11) solar masses, galaxy ages of 0.89 Gyr, redshifts in the range of approximately 2.1 to 2.4, and present no dust or star formation. Model fitting without the J and H fillter magnitudes show that galaxy age is not affected by the presence/absence of these filters, but mass and redshift are dependent on J and H filters. Without J and H filters, the mass and redshift are overestimated by a factor of 60% and 20% repsectively.