Astronomy and Astrophysics – Astrophysics
Scientific paper
1996-08-13
Mon.Not.Roy.Astron.Soc. 286 (1997) 257
Astronomy and Astrophysics
Astrophysics
MNRAS to be published, 11 pages with 6 figures using mn.sty
Scientific paper
Motivated by the suggestion of Kang, Ryu \& Jones (1996) that particles can be accelerated to high energies via diffusive shock acceleration process at the accretion shocks formed by the infalling flow toward the clusters of galaxies, we have calculated the expected particle flux from a cosmological ensemble of clusters. We use the observed temperature distribution of local clusters and assume a simple power-law evolutionary model for the comoving density of the clusters. The shock parameters such as the shock radius and velocity are deduced from the ICM temperature using the self-similar solutions for secondary infall onto the clusters. The magnetic field strength is assume to be in equipartition with the postshock thermal energy behind the accretion shock. We also assume that the injected energy spectrum is a power-law with the exponential cutoff at the maximum energy which is calculated from the condition that the energy gain rate for diffusive shock acceleration is balanced by the loss rate due to the interactions with the cosmic background radiation. In contrast to the earlier paper we have adopted here the description of the cosmic ray diffusion by Jokipii (1987) which leads to considerably higher particle energies. Finally the injected particle spectrum at the clusters is integrated over the cosmological distance to earth by considering the energy loss due to the interactions with the cosmic background radiation. Our calculations show that the expected spectrum of high-energy protons from the cosmological ensemble of the cluster accretion shocks could match well the observed cosmic ray spectrum near $10^{19}$eV with reasonable parameters and models if about $10^{-4}$ of the infalling kinetic energy can be injected into the intergalactic space as the high energy particles.
Biermann Peter L.
Kang Hyesung
Rachen Jorg P.
No associations
LandOfFree
Contributions to the Cosmic Ray Flux above the Ankle: Clusters of Galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Contributions to the Cosmic Ray Flux above the Ankle: Clusters of Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Contributions to the Cosmic Ray Flux above the Ankle: Clusters of Galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-358114