Ultra-high Energy Cosmic Rays and Neutron-Decay Halos from Gamma Ray Bursts

Abstract

Abstract. Simple arguments concerning power and acceleration efficiency show that ultra-high energy cosmic rays (UHECRS) with energies19 eV could originate from GRBs. Neutrons formed through photo-pion production processes in GRB blast waves leave the acceleration site and travel through intergalactic space, where they decay and inject a very energetic proton and electron component into intergalactic space. The neutron-decay protons form a component of the UHECRs, whereas the neutron-decay electrons produce optical/X-ray synchrotron and gamma radiation from Compton-scattered background radiation. A significant fraction of galaxies with GRB activity should be surrounded by neutron-decay halos of characteristic size ∼ 100 kpc.

Cosmic rays and neutrinos from GRBs: predictions versus acceleration modeling

“…Gamma Ray Bursts (hereafter GRBs) are unique high energy phenomena in astrophysics because of their possibility to manifest all the interesting "astroparticles" processes, such as generation of high energy gamma rays, ultra high energy cosmic rays, high energy neutrinos and gravitational waves (see Dermer (2001) and Mészáros (2002)). The "fireball" model (Rees & Mészáros 1992) has been successful in explaining the afterglow stage, and its more elaborated form with the addition of internal shocks (Rees & Mészáros (1994), Paczyński & Xu (1994)) during the "free" expansion has been successful in explaining the light curve and gamma spectra (Fishman & Meegan (1995), Beloborodov et al (2000)).…”