Program: GN-2010A-Q-1

Title:The Gemini Cluster Astrophysics Spectroscopic Survey (GCLASS)
PI:Gillian Wilson
Co-I(s): Howard Yee, Adam Muzzin, Michael Balogh, Kris Blindert, Douglas Burke, Shelly Bursick, Ricardo Demarco, Erica Ellingson, Jonathan Gardner, David Gilbank, Mike Gladders, Amalia Hicks, Henk Hoekstra, Mark Lacy, Subhabrata Majumdar, Alessandro Rettura, Jason Surace, Tracy Webb, Renbin Yan

Abstract

We propose for the penultimate semester of our GMOS spectroscopic survey of 10 rich clusters at z ~ 1.1 drawn from the SpARCS IR cluster survey. These data will be used in conjunction with multiwavelength optical/NIR/MIR photometry to measure the SFRs, stellar masses, ages, and merger rates of galaxies in high-redshift, high-density environments. We will also study the kinematics of clusters during their most active accretion phase, and determine velocity dispersions, which will allow the first calibration of mass-richness scaling relations for clusters at z > 1, a key component for cluster cosmology projects. Because they are selected from a deep, wide-field IR survey, the GCLASS clusters are massive, yet unbiased with respect to their X-ray luminosity. This unique selection criteria makes GCLASS complementary to previous studies of z > 1 X-ray selected clusters, as well as the low-mass z > 1 clusters selected from IR surveys that probe smaller volumes. This project takes advantage of the unique microslit capability of GMOS in band-shuffle mode which allows the compact placement of up to 55 slits in only a 3.0' x 1.7' area. Our previous allocations show that this capability makes GMOS ~ 4 times more efficient than Keck/DEIMOS or VLT/FORS2 at obtaining redshifts within the cluster virial radius at z > 1.

Publications using this program's data