2008/06/30 by Samuel W. Skillman, Brian W. O’Shea, Brian W. O'Shea +4 · 161 citations
Physics and Astronomy · #Acceleration #Adaptive mesh refinement #Astrophysics #Astrophysics and Cosmic Phenomena #COSMIC cancer database #Classical mechanics #Cosmic ray #Fermi acceleration #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Mach number #Mechanics #Particle acceleration #Physics #Redshift #Shock (circulatory) #Structure formation #astro-ph
paper · pdf · doi:10.1086/592496
published in The Astrophysical Journal 689(2), 1063-1077 (IOP Publishing) · 15 pages, 14 figures, Accepted to ApJ, minor changes made
arxiv created 2008/08/21 · openalex publication_date 2008/11/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present new results characterizing cosmological shocks within adaptive mesh refinement N -body/hydrodynamic simulations that are used to predict nonthermal components of large-scale structure. This represents the first study of shocks using adaptive mesh refinement. We propose a modified algorithm for finding shocks from those used on unigrid simulations that reduces the shock frequency of low Mach number shocks by a factor of ~3. We then apply our new technique to a large, (512 h −1 Mpc) 3 , cosmological volume and study the shock Mach number ( ) distribution as a function of preshock temperature, density, and redshift. Because of the large volume of the simulation, we have superb statistics that result from having thousands of galaxy clusters. We find that the Mach number evolution can be interpreted as a method to visualize large-scale structure formation. Shocks with < 5 typically trace mergers and complex flows, while 5 < < 20 and > 20 generally follow accretion onto filaments and galaxy clusters, respectively. By applying results from nonlinear diffusive shock acceleration models using the first-order Fermi process, we calculate the amount of kinetic energy that is converted into cosmic-ray protons. The acceleration of cosmic-ray protons is large enough that in order to use galaxy clusters as cosmological probes, the dynamic response of the gas to the cosmic rays must be included in future numerical simulations.