Star-forming fractions and galaxy evolution with redshift in rich X-ray-selected galaxy clusters
Abstract
We have compared stacked spectra of galaxies, grouped by environment and stellar mass, among 58 members of the redshift z = 1.24 galaxy cluster RDCS J1252.9-2927 (J1252.9) and 134 galaxies in the z = 0.84 cluster RX J0152.7-1357 (J0152.7). These two clusters are excellent laboratories to study how galaxies evolve from star-forming to passive at z ~ 1. We measured spectral indices and star-forming fractions for our density- and mass-based stacked spectra. The star-forming fraction among low-mass galaxies (< 7 x 10^10 M_sun) is higher in J1252.9 than in J0152.7, at about 4 sigma significance. Thus star formation is being quenched between z = 1.24 and z = 0.84 for a substantial fraction of low-mass galaxies. Star-forming fractions were also found to be higher in J1252.9 in all environments, including the core. Passive galaxies in J1252.9 have systematically lower D_n4000 values than in J0152.7 in all density and mass groups, consistent with passive evolution at modestly super-solar metallicities.
Keywords
Cite
@article{arxiv.1306.3431,
title = {Star-forming fractions and galaxy evolution with redshift in rich X-ray-selected galaxy clusters},
author = {J. B. Nantais and A. Rettura and C. Lidman and R. Demarco and R. Gobat and P. Rosati and M. J. Jee},
journal= {arXiv preprint arXiv:1306.3431},
year = {2015}
}
Comments
18 pages, 14 figures, accepted for publication in A&A