Program: GS-2014B-Q-64

Title:Spectroscopy of Galaxies in Massive Clusters: \\ Galaxy Properties and Dynamical \\ Cluster Mass Calibration
PI:Christopher W Stubbs
Co-I(s): M L N Ashby

Abstract

We propose to acquire GMOS spectroscopy of $85$ clusters of galaxies selected via the Sunyaev-Zel'dovich (SZ) effect from the South Pole Telescope (SPT) microwave background survey. This will bring our total to 100 SPT clusters with velocity dispersions. The SPT survey is delivering a uniformly-selected high-mass cluster sample that is essentially volume-complete beyond $z>$0.3. We will target a subset ($0.3 < z < 0.8$) of the SPT cluster catalog, extracted from $2500 \,\mathrm{deg}^2$. This data set will establish competitive, independent constraints on cosmological parameters, including the nature of the dark energy. Achieving this goal requires a precise understanding of the relationship between the cluster's SZ signature and the cluster mass, and this mass normalization is currently the largest systematic error in SPT's cosmological constraints. One promising method of determining galaxy cluster masses is to probe the dark matter potential with galaxy velocities. Using data from a large cluster sample will average over random projection effects, and will enable the calibration of the SZ-mass scaling relation, in conjunction with X-ray and lensing data on a smaller sample. The cluster galaxy spectroscopy we obtain will also equip the community to address a wide range of questions in galaxy evolution and cluster astrophysics.

Publications using this program's data