Speaker: Daniel Wik (University of Utah) 

Host: Jake Simon

Title: Galaxy Clusters in a Cosmological Context

Abstract:

As the largest gravitationally bound objects in the universe, forming relatively recently in cosmic time, the space and mass distributions of galaxy clusters are sensitive probes of the underlying cosmology---driven largely by dark matter and dark energy---in which clusters grow.  Obtaining accurate galaxy cluster masses is therefore crucial.  However, the primary method for deriving cluster masses relies on the hot X-ray emitting gas between galaxies, which results in masses ~40% lower than expected in the currently preferred cosmological model.  I will discuss various factors contributing to this discrepancy, including modeling assumptions and instrumental calibration uncertainties---none of which can satisfactorily account for the entirety of the bias---and the implications for clusters physics and/or our understanding of cosmology.