Relativistic Plasma Probes of Low Overdensity Environments

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AST-0607674JonesA large fraction of baryons in the low-z universe reside in hard-to-observe gaseous low-density settings, which contain crucial information about the evolution of the cosmic web. There is an increasing appreciation that this evolution is heavily influenced by magnetized relativistic particle populations, that is, relativistic plasmas. Synchrotron and non-thermal X-ray emissions from these plasmas also serve as unique observational diagnostics of environmental physical conditions. This project is an ambitious suite of theoretical and observational studies of these relativistic plasmas and their interactions with the surrounding thermal plasmas. It includes: a survey of filaments of galaxies for shocks due to infall, using rotation measure synthesis; measuring the local pressures in regions of low galactic and baryon density using radio galaxies; exploring the intra-group medium through studies of mini-halos of synchrotron radiation; the first 3D simulations of radio galaxy evolution, including magnetic fields and radiant relativistic plasmas, in realistic, inhomogeneous low density cosmological environments; and investigation of emissions from cosmic rays in large scale cosmic structure shocks and in super-wind terminal shocks, including nonlinear feedback on flows and associated MHD turbulence. The combination of unique multidimensional MHD simulations with realistic synthetic observations will identify the optimal physical analysis methods to apply to real observations. The synergy between the observational and theoretical efforts will greatly enhance the value of the insights to be gained from each alone.This research will train undergraduate and graduate students in both cutting edge science and the development of innovative data analysis and numerical simulation techniques. The team has a commitment to spreading their results, including work with the local planetarium, K-12 public schools, and community groups.