Gerbal, in press SHOCKS AND NONTHERMAL PROCESSES IN CLUSTERS

Cluster Merger Shock Constraints on Particle Acceleration and Nonthermal Pressure in the Intracluster Medium

X-ray observations of galaxy cluster merger shocks can be used to constrain nonthermal processes in the intracluster medium (ICM). The presence of nonthermal pressure components in the ICM, as well as the shock acceleration of particles and their escape, all affect shock jump conditions in distinct ways. Therefore, these processes can be constrained usingX-ray surface brightness and temperature...

Nonthermal radiation from clusters of galaxies: the role of merger shocks in particle acceleration

Nonthermal radiation is observed from clusters of galaxies in the radio, hard X-rays, and possibly in the soft X-ray/UV bands. While it is known that radiative processes related to nonthermal electrons are responsible for this radiation, the sites and nature of particle acceleration are not known. We investigate here the acceleration of protons and electrons in the shocks originated during merg...

Shock Acceleration and gamma radiation in Clusters of Galaxies

The nonthermal radiation observed from a handfull of clusters of Galaxies is the proof that particle acceleration occurs in the intracluster medium. It is often believed that shock surfaces associated with either mergers of clusters of galaxies, or with the cosmological inflow of matter onto clusters during structure formation may be the sites for acceleration. We discuss here the effectiveness...

Shocks and Nonthermal Processes in Clusters

Merger Shocks and Nonthermal Processes in Clusters of Galaxies

Clusters of galaxies generally form by the gravitational merger of smaller clusters and groups. Major cluster mergers are the most energetic events in the Universe since the Big Bang. Mergers drive shocks into the intracluster gas, and these shocks heat the intracluster gas, and should also accelerate nonthermal relativistic particles. The thermal effects of merger shocks will be briefly discus...