6,686 research outputs found
Which acceleration process for UHE-Cosmic Rays in Gamma Ray Bursts ?
In this paper, we have made an accurate investigation of proton acceleration
in GRBs and we have predicted a possible signature of cosmic rays, in a
sufficiently baryon-loaded fireball, via GeV -ray emission produced by
-meson decay. If two ungrounded assumptions are removed, namely,
Bohm's scaling and a slow magnetic field decrease, the usual Fermi processes
are unable to generate ultra high energy cosmic rays (UHECRs) in GRBs. We
propose to develop another scenario of relativistic Fermi acceleration in the
internal shock stage. We present the results of a realistic Monte-Carlo
simulation of a multi-front acceleration which clearly shows the possible
generation of UHECR. The amount of energy converted into UHECRs turns out to be
a sizeable fraction of the magnetic energy.Comment: 22 pages, accepted for publication in A&
Synchrotron Emissions in GRB Prompt Phase Using a Semi Leptonic and Hadronic Model
In this communication devoted to the prompt emission of GRBs, we claim that
some important parameters associated to the magnetic field, such as its index
profile, the index of its turbulence spectrum and its level of irregularities,
will be measurable with GLAST. In particular the law relating the peak energy
Epeak with the total energy E (like Amati's law) constrains the turbulence
spectrum index and, among all existing theories of MHD turbulence, is
compatible with the Kolmogorov scaling only. Thus, these data will allow a much
better determination of the performances of GRBs as particle accelerators. This
opens the possibility to characterize both electron and proton acceleration
more seriously. We discuss the possible generation of UHECRs and of its
signature through GeV-TeV synchrotron emission.Comment: 30th International Cosmic Ray Conference (ICRC2007) - Proceeding
#107
Alien Registration- Pelletier, George D. (Fort Kent, Aroostook County)
https://digitalmaine.com/alien_docs/36323/thumbnail.jp
Alien Registration- Pelletier, Arthur D. (Topsham, Sagadahoc County)
https://digitalmaine.com/alien_docs/9373/thumbnail.jp
- …