Authors: Jack Burns, Sam Skillman, & Greg Salvesen, University of Colorado at Boulder
Colliding galaxy clusters are insightful astrophysical plasma laboratories. Shocks produced during mergers heat the intracluster medium (ICM), assisting the gas to achieve roughly hydrostatic equilibrium with the cluster gravitational potential well. Shocks also play a key role for the nonthermal component of the ICM. Shocks compress and amplify magnetic fields, and they accelerate cosmic rays (CR) via a diffusive Fermi process. Thus, merger shocks are illuminated via the resulting synchrotron radiation arising from relativistic CR electrons gyrating in ICM B-fields producing steep-spectrum, so-called “radio relics”. By combining high resolution Enzo AMR cosmological simulations with an accurate shock finding algorithm and a model for electron acceleration, we calculate the expected synchrotron emission, along with synthetic X-ray temperature and SZE images, resulting from cosmological structure formation. I will present a new methodology for producing adaptively-binned XMM-Newton/Chandra X-ray temperature maps from joint spectral fitting and apply our shock-finding routine (developed from AMR simulations) to two observed clusters (A85 and A3667) to probe the underlying Mach number distribution. I will also show synthetic radio maps, scaling relations, and a radio luminosity function for a large sample of numerical galaxy clusters. By producing observationally motivated statistics, we provide predictions that can be compared with observations to further our understanding of merger shocks, electron shock acceleration, and the kinematic structure of galaxy clusters.
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