DELAYED ONSET OF HIGH-ENERGY EMISSIONS IN LEPTONIC AND HADRONIC MODELS OF GAMMA-RAY BURSTS

Journal Article · Mon Oct 01 00:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/757/2/115· OSTI ID:22092214

Asano, Katsuaki ^[1]; Meszaros, Peter ^[2]

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1. Interactive Research Center of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)
2. Department of Astronomy and Astrophysics, Department of Physics, Center for Particle and Gravitational Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

The temporal-spectral evolution of the prompt emission of gamma-ray bursts is simulated numerically for both leptonic and hadronic models. For weak enough magnetic fields, leptonic models can reproduce the few seconds delay of the onset of GeV photon emission observed by Fermi-LAT, due to the slow growth of the target photon field for inverse Compton scattering. For stronger magnetic fields, the GeV delay can be explained with hadronic models, due to the long acceleration timescale of protons and the continuous photopion production after the end of the particle injection. While the FWHMs of the MeV and GeV light curves are almost the same in one-zone leptonic models, the FWHMs of the 1-30 GeV light curves in hadronic models are significantly wider than those of the 0.1-1 MeV light curves. The amount of the GeV delay depends on the importance of the Klein-Nishina effect in both the leptonic and hadronic models. In our examples of hadronic models the energies of the escaped neutrons are comparable to the gamma-ray energy, although their contribution to the ultra high-energy cosmic rays is still subdominant. The resulting neutrino spectra are hard enough to avoid the flux limit constraint from IceCube. The delay of the neutrino emission onset is up to several times longer than the corresponding delay of the GeV photon emission onset. The quantitative differences in the light curves for various models may be further tested with future atmospheric Cerenkov telescopes whose effective area is larger than that of Fermi-LAT, such as CTA.

• OSTI ID: 22092214
• Journal Information: Astrophysical Journal, Vol. 757, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCELERATION
ASTROPHYSICS
COMPTON EFFECT
COMPUTERIZED SIMULATION
COSMIC GAMMA BURSTS
GAMMA RADIATION
GEV RANGE
KLEIN-NISHINA FORMULA
MAGNETIC FIELDS
MEV RANGE
NEUTRINO DETECTION
NEUTRINOS
NEUTRONS
PARTICLE MODELS
PHOTON EMISSION
PHOTONS
PROTONS
TELESCOPE COUNTERS
VISIBLE RADIATION