The Dynamics and Afterglow Radiation of Gamma-Ray Bursts

Andrew MacFadyen

January 12, 2012

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Abstract: Gamma-ray bursts produce afterglow radiation as they drive strong relativistic shocks into the surrounding medium. The explosion energy is beamed into narrow jets which initially do not spread significantly due to relativistic kinematics. As the shock decelerates, lateral spreading ensues and the blastwave slowly transitions into a spherical non-relativistic shock. I will discuss recent progress in understanding the dynamics of this process, as well as the radiative signatures received by observers at arbitrary angles with respect to the jet axis. I will then discuss new relativistic MHD simulations of turbulent amplification of magnetic field relevant for afterglow radiation as well as for neutron star mergers. If time permits, I will also briefly discuss very recent work on low-mass protoplanet migration. These topics are connected by recent developments in numerical hydrodynamics including the use of dynamical computational meshes.