Constraining modified gravity models using galaxy cluster masses

          @misc{ pirsa_PIRSA:24070067,
            doi = {10.48660/24070067},
            url = {https://pirsa.org/24070067},
            author = {Butt, Minahil Adil},
            keywords = {},
            language = {en},
            title = {Constraining modified gravity models using galaxy cluster masses},
            publisher = {Perimeter Institute},
            year = {2024},
            month = {jul},
            note = {PIRSA:24070067 see, \url{https://pirsa.org}}
          }
          

Abstract

We present a comprehensive joint analysis of two distinct methodologies for measuring the masses of galaxy clusters: hydrostatic measurements and caustic techniques. We show that by including cluster-specific assumptions obtained from hydrostatic measurements in the caustic method, the potential mass bias between these approaches can be significantly reduced. While this may appear to diminish the caustic method as a technique independent of the dynamical state of a cluster, it provides a means to refine mass constraints and offers an avenue for scrutinizing modifications to gravity. Applying this approach to two well-observed massive galaxy clusters A2029 and A2142, we find no discernible mass bias, affirming the method's validity. We draw a similar conclusion when applying this approach to modified gravity models. Specifically, our implementation allows us to investigate Chameleon and Vainshtein screening mechanisms, enhancing our understanding of these modified gravity scenarios. Furthermore, we explore the prospect of achieving more precise constraints with fewer systematic errors by exclusively employing the caustic method to constrain screening mechanisms on a larger scale, encompassing several hundred stacked galaxy clusters.