Astronomy Colloquium Series

Cluster Cosmology with the South Pole Telescope

The South Pole Telescope (SPT) is a 10-meter millimeter-wavelength telescope located at the geographic South Pole, one of the world’s premier sites for millimeter-wave observations. The SPT has been used to conduct several wide-area surveys including the 2500-square-degree SPT-SZ survey (2007-2011) and two recently-completed surveys conducted using the SPTpol receiver: the 500-square-degree SPTpol Survey (which reached depths of 5.3 uK-arcmin at 150 GHz, ~3x deeper than SPT-SZ) and the SPTpol Extended Cluster Survey which covered an additional 2500-square-degrees to somewhat shallower depths than SPT-SZ.

One of the primary objectives of the wide-area SPT surveys has been the construction of a mass-limited sample of galaxy clusters identified via the thermal Sunyaev- Zel’dovich (SZ) effect, through which massive clusters imprint subtle temperature distortions on the cosmic microwave background. The abundance of such clusters is a powerful cosmological probe as it depends sensitively upon both the expansion history of the universe and the growth of density fluctuations. In this talk I will discuss progress analyzing these three datasets including updated cosmological constraints from the initial SPT-SZ cluster sample using new weak lensing data as well as ongoing work from a new project characterizing the strong lensing properties of these systems. The results presented in this talk will be significantly improved with data from the new SPT-3G survey---deployed in January 2017---that will identify an order of magnitude more clusters than previous generation SZ surveys.