Session L4: Invited Session: Galaxy Clusters Across the EM Spectrum

Cluster Cosmology from Large Optical Surveys

Upcoming optical surveys will allow us to explore the formation of structure in the Universe across half of its history. This data will place tight constraints on dark energy, departures from general relativity, and even the sum of neutrino masses. I will review how cluster cosmology will inform these questions, placing a special emphasis on the potential pitfalls of cluster cosmology, and how we plan to approach these with optical data.   

SZ Cluster Surveys and Cosmology

Recent millimeter-wave surveys from instruments such as the Atacama Cosmology Telescope (ACT), the South Pole Telescope (SPT), and the Planck satellite have been able to blindly detect galaxy clusters through the Sunyaev-Zel'dovich (SZ) effect. The SZ effect is a powerful technique for detecting galaxy clusters as it is independent of cluster distance. In turn, the number of galaxy clusters that exist over cosmic time is a powerful probe of cosmology and fundamental physics. I will discuss constraints on cosmology using SZ clusters detected with ACT. I will also review a newly detected secondary SZ effect, called the kinetic SZ effect, and its potential use for cosmology. The challenges that arise when using these techniques will also be discussed, as well as ways forward.