Collisionless Shock Waves and the Origin of Cosmic Rays
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.
Figure 2: Synchrotron emission simulation of the Crab Nebula.
Source: Komissarov S.S. Lyubarsky Y.E. 2003, MNRAS, 344, L93.
Manifestations of Exotic and New Physics in Nature
We examine astrophysical consequences of extreme, exotic, and new physics.
In Gamma Ray Bursts, for example, general relativistic effects , especially the event horizon of the black hole, may play a crucial role. We examine whether observations can reveal these effects and the existence of the event horizon. Preliminary results suggest that general relativity may be crucial to understanding the qualitative nature of gamma ray bursts.
In magnetars, collapsed stars with extraordinarily high magnetic fields, the strength of the magnetic alters the nature of quantum electrodynamics (The magnetic field-particle spin interaction term in the Langrangian exceeds the elecron rest mass). The vacuum develops an index of refraction that affects the propagation of light. Condensed matter, e.g. the crust of the magnetar, is strongly affected by such a magnetic field. We attempt to understand the effects of the ultrastrong magnetic fields on the observed phenomena.
In cosmology, we attempt to understand dark energy, which is matter with negative pressure, as a field that is generated by dark matter. This hypothesis aims to resolve the present mystery as to why dark matter and dark energy both presently exist in the universe in comparable quantities.