The Astrophysical Journal · 1995 · 565 citations · 0 references
Natural SciencesAstronomyPhysicsAstrophysicsGamma-ray AstronomyGravitationGamma-ray BurstsHigh-energy AstrophysicsActive Galactic Nuclei ContributionCosmic-ray AccelerationExternal ShocksGalactic Cosmic RaysInternal ShocksObservational ConstraintsUltra-high-energy Cosmic RaysUltrahigh-energy Cosmic Rays
Ultra‑high‑energy cosmic rays are isotropic, reach energies ≳3×10^20 eV, and conventional models cannot explain both their isotropy and energy, while the photopion catastrophe that limits acceleration in active galactic nuclei is avoided in gamma‑ray bursts. The study demonstrates that acceleration of UHECRs in gamma‑ray bursts satisfies observational constraints and proposes a test based on the sky distribution of UHECRs. Using the Mészáros–Rees hyperrelativistic shock model for GRBs, the author shows that the maximum attainable energy is ≈10^20 eV, matching the Bird et al. event without requiring beaming. The model reproduces the observed UHECR energy spectrum and total flux at Earth, confirming that GRBs can accelerate particles to the required energies.
view Abstract Citations (543) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Acceleration of Ultra--High-Energy Cosmic Rays in Gamma-Ray Bursts Vietri, Mario Abstract Ultra-high-energy cosmic rays (UHECRs) are roughly isotropic and attain very large energies, E ≳ 3 × 1020 eV. Conventional models fail to explain both facts. I show here that acceleration of UHECRs in gamma-ray bursts (GRBs) satisfies both observational constraints. Using the Mészáros & Rees model (see their recent work) of GRBs as due to hyperrelativistic shocks, I show that the highest energies that can be attained thusly are E ≌ 1020 θ-5/3/ n15/6 eV, explaining the energy of the Bird et al. event (described in their recent work) even without beaming. The traditional photopion catastrophe affecting UHECR acceleration in active galactic nuclei is circumvented. An order of magnitude estimate shows that the total energy flux of UHECRs at Earth is also correctly reproduced. A test of the model based upon the UHECRs' distribution upon the plane of the sky is briefly discussed. Publication: The Astrophysical Journal Pub Date: November 1995 DOI: 10.1086/176448 arXiv: arXiv:astro-ph/9506081 Bibcode: 1995ApJ...453..883V Keywords: ACCELERATION OF PARTICLES; ISM: COSMIC RAYS; GAMMA RAYS: BURSTS; Astrophysics E-Print: 20 pages, latex (AASTEX needed), no figures, to appear in ApJ, November 10 1995 issue full text sources arXiv | ADS |