Measuring the Growth of Structure with Spectroscopically Identified Groups and Clusters

Author(s): Davis, M; Gerke, BF; Coil, AL; Cooper, MC; Yan, R; Newman, JA; Faber, SM; Koo, D; Guhathakurta, P | Abstract: Number counts of galaxy clusters offer a very promising probe of the Dark Energy (DE) equation-of-state parameter, $w$. The basic goal is to measure abundances of these objects as a function of redshift, compare this to a theoretical prediction, and infer the values of cosmological parameters. Various teams have proposed such a measurement, including the South Pole Telescope, the Dark Energy Survey and the Red-Sequence Cluster Survey. The specific study discussed here detects clusters and smaller galaxy groups in the three-dimensional distribution of galaxies inferred from a large spectroscopic redshift survey. This method allows the abundance, $N$, of groups and clusters to be measured as a function of \emph{velocity dispersion}, as well as of redshift, permitting a more sensitive test of cosmology.