A Parametrized Galaxy Catalog Simulator For Testing Cluster Finding, Mass Estimation and Photometric Redshift Estimation in Optical and Near Infrared Surveys

摘要

We present a galaxy catalog simulator which turns N-body simulations withsubhalos into multiband photometric mocks. The simulator assigns galaxyproperties to each subhalo to reproduce the observed cluster galaxy halooccupation distribution, the radial and mass dependent variation in fractionsof blue galaxies, the luminosity functions in clusters and the field, and thered-sequence in clusters. Moreover, the evolution of these parameters is tunedto match existing observational constraints. Field galaxies are sampled fromexisting multiband photometric surveys using derived galaxy photometricredshifts. Parametrizing an ensemble of cluster galaxy properties enables us tocreate mock catalogs with variations in those properties, which in turn allowsus to quantify the sensitivity of cluster finding to current observationaluncertainties in these properties. We present an application of the catalog simulator to characterize theselection function of a galaxy cluster finder that utilizes the clusterred-sequence galaxy clustering on the sky, in terms of completeness andcontamination. We estimate systematic uncertainties due to the observationaluncertainties on our simulator parameters in determining the selection functionusing five different sets of modified catalogs. Our estimates indicate thatthese uncertainties are at the $\le15$% level with current observationalconstraints on cluster galaxy populations and their evolution. In addition, weexamine the $B_{gc}$ parameter as an optical mass indicator and measure theintrinsic scatter of the $B_{gc}$--mass relation to be approximately log normalwith $\sigma_{\log_{10}M}\sim0.25$. Finally, we present tests of a red sequenceoverdensity redshift estimator using both simulated and real data, showing thatit delivers redshifts for massive clusters with $\sim$2% accuracy out toredshifts $z\sim0.5$ with SDSS-like datasets.