Jack Hughes

Rutgers, the State University of New Jersey

Clusters and Cosmology from the Atacama Cosmology Telescope

The Atacama Cosmology Telescope (ACT) is a 6-m diameter telescope with a sensitive mm-wave band camera custom designed to survey the cosmic microwave background (CMB) on arcminute angular scales. The camera observes simultaneously in three bands at frequencies of 148 GHz, 220 GHz, and 270 GHz. One of the goals of the project is to find galaxy clusters through the Sunyaev-Zel'dovich effect, which arises when hot electrons in the cluster inverse Compton scatter cold CMB photons. The SZ effect manifests as a decrement in ACT's low frequency channel, an increment in its high frequency channel, and a null in the middle channel. Over the past year the ACT team has pursued an ambitious program to identify and characterize the ACT clusters and utilize them to constrain the growth of structure in the Universe. In this colloquium I will present our current results and describe our plans for the future.