Collisionless Shock Waves and the Origin of Cosmic Rays

David Eichler

Astronomy in the radio, X-ray, and gamma ray and ultrahigh energy gamma ray frequency bands is made possible largely by relativistic particles, which emit at these frequencies when their paths are bent by magnietic fields. The Crab Nebula is but one famous example of synchrotron radio, X-rays and gamma rays being emitted by electrons moving at 0.999999 of the speed of light. We attempt to understand how, and under what circumstances, violent explosions accelerate a small minority of particles to such enormous energies.

 



Figure 1: The Crab Nebula in X-ray.
Credits: X-ray: NASA/CXC/ASU/J. Hester et al.; Optical: NASA/HST/ASU/J. Hester et al.
Source: http://chandra.harvard.edu/photo/2002/0052/more.html

Figure 2: Synchrotron emission simulation of the Crab Nebula.
Source: Komissarov S.S. Lyubarsky Y.E. 2003, MNRAS, 344, L93.