Probing Cosmic Acceleration with Galaxy Clusters

Hao-Yi Wu (Ohio State)

The acceleration of the Universe is one of the biggest puzzles in physics: is it due to a cosmological constant, dynamical dark energy, or modification of gravity?  Galaxy clusters provide a unique opportunity to answer this question.  In this talk, I will first discuss how we use large sky surveys of galaxy clusters to study cosmic acceleration.  In these surveys, a major challenge is to accurately calibrate the mass of clusters.  I will then present my research on using simulations to improve mass calibration methods, including galaxy dynamics, weak gravitational lensing, and X-ray observations.  These results not only mitigate the systematic errors in current cluster surveys but also help the optimization of future ground- and space-based missions.