Using Radio Relics to Help Reconstruct the Dynamics of Galaxy Cluster Mergers*

Merging galaxy clusters are a unique environment in which to probe the behavior and properties of dark matter. To best understand these properties, one must be able to reconstruct the dynamics of these massive events. Given that these events occur over billions of years, we cannot directly observe many of the parameters dictating the evolution of these events, and therefore must infer them through various methods. Previous work by Wittman inferred these parameters from simulated analog mergers recorded from a cosmological n-body simulation (BigMDPL). This work develops a mathematical model that could estimate the projected position of the shock wave that is launched at pericenter crossing. In systems where the shock is visible as a radio "relic" or X-ray discontinuity, this allows us to constrain the viewing angle and time since pericenter. This model was implemented into existing code to analyze hundreds of analog clusters to estimate the parameters of a similar real-world observation. This method was used to examine the Sausage (CIZA J2242. 8+5301) as well as the Bullet Cluster (1E 0657-56) and compared to established consensus.