Abstract
Galaxy clusters play an important role in modern cosmology. As the most massive, virialized objects in the universe, their abundance across cosmic time provides unique constraints on the nature of dark matter and dark energy. The power of galaxy clusters as cosmological probes depends on our ability to measure galaxy cluster masses accurately. The recent result from the Planck Satellite highlights the importance of accurate galaxy cluster mass in resolving the tension in the cosmological constraints derived from the primary anisotropies of the cosmic microwave background, and those from galaxy cluster counts.
In this talk, I will present results from the "Omega500" simulation, a high-resolution hydrodynamic simulation of galaxy cluster formation that follows the evolution of dark matter and baryons in a realistic cosmological setting. We address some of the key physical processes responsible for biasing galaxy cluster masses. In particular, we show that non-equilibrium physics in the outskirts of galaxy clusters, such as gas turbulence, clumping, and non-equilibrium electrons, introduce significant biases in the X-ray and Sunyaev-Zeldovich mass estimates of galaxy clusters. I will outline efforts and challenges ahead in addressing these physical processes for improving cosmological constraints to the percent-level with upcoming galaxy cluster surveys.
Coffee and tea will be served 20 minutes prior to the seminar.