Simulations of relativistic, collisionless shocks: The X-ray hot spots in the M87 jet
Ken-Ichi Nishikawa (NSSTC/UAH) , P. Hardee (UA), Y. Mizuno (NASA/NSSTC), G.J. Fishman (NASA/MSFC), D. Hartmann (Clemson Univ.), M. Medvedev (Univ. Kansas).
We studied collisionless shocks and their associated emissions in an effort to model the X-ray hot spots observed in the jet of M87. In collisionless shocks, the Weibel instability is responsible for particle acceleration and magnetic field generation. Particle In Cell (PIC) simulations of relativistic, collisionless shocks show that particle acceleration is provided in situ by the Weibel instability, which produces current filaments and associated magnetic fields. Particles develop a velocity distribution with higher energy a tail due to the acceleration in small-scale, highly non-uniform, amplified magnetic fields. The resulting jitter radiation from electrons in these non-uniform fields can have very different spectral properties than synchrotron radiation. We report recent results of our PIC simulations and relate them to X-ray observations with Chandra.