Rita Tojeiro, Will Percival, David A. Wake, Claudia Maraston, Ramin A. Skibba, Idit Zehavi, Ashley J. Ross, Charlie Conroy, Hong Guo, Marc Manera, Karen L. Masters, Janine Pforr, Lado Samushia, Donald P. Schneider, Daniel Thomas, Dmitry Bizyaev, Howard Brewington, Elena Malanushenko, Viktor Malanushenko, Daniel Oravetz, Kaike Pan, Alaina Shelden, Audrey Simmons, Stephanie Snedden
We present a comprehensive study of 250,000 galaxies targeted by the Baryon Oscillation Spectroscopic Survey (BOSS) up to z {\approx} 0.7 with the specific goal of identifying and characterising a population of galaxies that has followed passive evolution (no mergers) as closely as possible. We compute a likelihood that each BOSS galaxy is a progenitor of the Luminous Red Galaxies (LRGs) sample, targeted by SDSS-I/II up z {\approx} 0.5, by using the fossil record of LRGs and their inferred star-formation histories, metallicity histories and dust content. We determine merger rates, luminosity growth rates and the evolution of the large-scale clustering between the two surveys, and we investigate the effect of using different stellar population synthesis models in our conclusions. We demonstrate that our sample is slowly evolving (of the order of 2 {\pm} 1.5% Gyr-1 by merging) by computing the change in weighted luminosity-per-galaxy between the two samples, and that this result is robust to our choice of stellar population models. Our conclusions refer to the bright and massive end of the galaxy population, with Mi0.55 < -22, and M* > 1e11.2M{\odot}, corresponding roughly to 95% and 40% of the LRGs and BOSS galaxy populations, respectively. Our analysis further shows that any possible excess of flux in BOSS galaxies, when compared to LRGs, from potentially unresolved targets at z {\approx} 0.55 must be less than 1% in the r0.55-band (approximately equivalent to the g-band in the rest-frame of galaxies at z = 0.55). We find an evolution of the large-scale clustering that is consistent with dynamical passive evolution, assuming a standard cosmology. We conclude that our likelihoods give a weighted sample that is as clean and as close to passive evolution (in dynamical terms) as possible, and that is optimal for cosmological studies.
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http://arxiv.org/abs/1202.6241
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