THE HIGH ENERGY BUDGET ALLOCATIONS IN SHOCKS AND GAMMA RAY BURSTS

Journal Article · Sun Oct 10 00:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/722/1/543· OSTI ID:21464679

Eichler, David ^[1]; Guetta, Dafne ^[2]; Pohl, Martin ^[3]

---

1. Physics Department, Ben-Gurion University, Be'er-Sheva 84105 (Israel)
2. Osservatorio astronomico di Roma, v. Frascati 33, 00040 Monte Porzio Catone (Italy)
3. Institut fuer Physik und Astronomie, Universitaet Potsdam, 14476 Potsdam-Golm (Germany)

The statistical distribution of energies among particles responsible for long gamma-ray burst (GRB) emission is analyzed in light of recent results of the Fermi Observatory. The all-sky flux, F{sub {gamma}}, recorded by the Gamma-Ray Burst Monitor (GBM) is shown, despite its larger energy range, to be not significantly larger than that reported by the Burst and Transient Explorer, suggesting a relatively small flux in the 3-30 MeV energy range. The present-day energy input rate in {gamma}-rays recorded by the GBM from long GRBs is found, assuming star formation rates in the literature, to be W-dot(0)=0.5 F{sub {gamma}H}/c=5x10{sup 42}erg Mpc{sup -3} yr{sup -1}. The Large Area Telescope fluence, when observed, is about 5%-10% per decade of the total, in good agreement with the predictions of saturated, nonlinear shock acceleration. The high-energy component of long GRBs, as measured by Fermi, is found to contain only {approx}10{sup -2.5} of the energy needed to produce ultrahigh-energy cosmic rays (UHECRs) above 4 EeV, assuming the latter to be extragalactic, when various numerical factors are carefully included, if the cosmic-ray source spectrum has a spectral index of -2. The observed {gamma}-ray fraction of the required UHECR energy is even smaller if the source spectrum is softer than E {sup -2}. The AMANDA II limits rule out such a GRB origin for UHECRs if much more than 10{sup -2} of the cosmic-ray energy goes into neutrinos that are within, and simultaneous with, the {gamma}-ray beam. It is suggested that 'orphan' neutrinos out of the {gamma}-ray beam might be identifiable via orphan afterglow or other wide angle signatures of GRBs in lieu of coincidence with prompt {gamma}-rays, and it is recommended that feasible single neutrino trigger criteria be established to search for such coincidences.

• OSTI ID: 21464679
• Journal Information: Astrophysical Journal, Vol. 722, Issue 1; Other Information: DOI: 10.1088/0004-637X/722/1/543; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCELERATION
AFTERGLOW
COSMIC GAMMA BURSTS
COSMIC NEUTRINOS
COSMIC RAY SOURCES
EEV RANGE
ENERGY BALANCE
GAMMA RADIATION
PHOTON EMISSION
STARS
TELESCOPES
COSMIC RADIATION
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
EMISSION
ENERGY RANGE
FERMIONS
IONIZING RADIATIONS
LEPTONS
MASSLESS PARTICLES
NEUTRINOS
PRIMARY COSMIC RADIATION
RADIATIONS