The low energy spectra of gamma-ray bursts

1982 ◽  
Author(s):  
R. W. Bussard ◽  
F. K. Lamb
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Low Energy ◽  
Energy Spectra

scholarly journals Low-energy Spectra of Gamma-Ray Bursts from Cooling Electrons

2018 ◽  
Vol 234 (1) ◽  
pp. 3 ◽  
Author(s):  
Jin-Jun Geng ◽  
Yong-Feng Huang ◽  
Xue-Feng Wu ◽  
Bing Zhang ◽  
Hong-Shi Zong
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Low Energy ◽  
Energy Spectra

scholarly journals Limits on quantum gravity effects from Swift short gamma-ray bursts

2017 ◽  
Vol 607 ◽  
pp. A121 ◽  
Author(s):  
M. G. Bernardini ◽  
G. Ghirlanda ◽  
S. Campana ◽  
P. D’Avanzo ◽  
J.-L. Atteia ◽  
...  
Keyword(s):  
Quantum Gravity ◽  
Gamma Ray ◽  
Lorentz Invariance ◽  
Spectral Energy Distribution ◽  
Gamma Ray Bursts ◽  
Low Energy ◽  
Energy Separation ◽  
Spectral Energy ◽  
Spectral Evolution ◽  
Short Grbs

The delay in arrival times between high and low energy photons from cosmic sources can be used to test the violation of the Lorentz invariance (LIV), predicted by some quantum gravity theories, and to constrain its characteristic energy scale EQG that is of the order of the Planck energy. Gamma-ray bursts (GRBs) and blazars are ideal for this purpose thanks to their broad spectral energy distribution and cosmological distances: at first order approximation, the constraints on EQG are proportional to the photon energy separation and the distance of the source. However, the LIV tiny contribution to the total time delay can be dominated by intrinsic delays related to the physics of the sources: long GRBs typically show a delay between high and low energy photons related to their spectral evolution (spectral lag). Short GRBs have null intrinsic spectral lags and are therefore an ideal tool to measure any LIV effect. We considered a sample of 15 short GRBs with known redshift observed by Swift and we estimate a limit on EQG ≳ 1.5 × 1016 GeV. Our estimate represents an improvement with respect to the limit obtained with a larger (double) sample of long GRBs and is more robust than the estimates on single events because it accounts for the intrinsic delay in a statistical sense.

Energy spectra of the cosmic gamma-ray bursts

1983 ◽  
Author(s):  
E. P. Mazets ◽  
S. V. Golenetskii ◽  
Yu. A. Guryan ◽  
R. L. Aptekar ◽  
V. N. Ilyinskii ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Energy Spectra

scholarly journals Evidence of two spectral breaks in the prompt emission of gamma-ray bursts

2019 ◽  
Vol 625 ◽  
pp. A60 ◽  
Author(s):  
M. E. Ravasio ◽  
G. Ghirlanda ◽  
L. Nava ◽  
G. Ghisellini
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Low Energy ◽  
Emission Region ◽  
Peak Energy ◽  
Standard Scenario ◽  
Low Magnetic Field ◽  
Short Grbs ◽  
Prompt Emission ◽  
Good Agreement

The long-lasting tension between the observed spectra of gamma-ray bursts (GRBs) and the predicted synchrotron emission spectrum might be solved if electrons do not completely cool. Evidence of incomplete cooling was recently found in Swift GRBs with prompt observations down to 0.1 keV, and in one bright Fermi burst, GRB 160625B. Here we systematically search for evidence of incomplete cooling in the spectra of the ten brightest short and long GRBs observed by Fermi. We find that in eight out of ten long GRBs there is compelling evidence of a low-energy break (below the peak energy) and good agreement with the photon indices of the synchrotron spectrum (respectively −2/3 and −3/2 below the break and between the break and the peak energy). Interestingly, none of the ten short GRBs analysed shows a break, but the low-energy spectral slope is consistent with −2/3. In a standard scenario, these results imply a very low magnetic field in the emission region (B′∼10 G in the comoving frame), at odd with expectations.

Search for low-energy neutrino radiation accompanying gamma-ray bursts on the Baksan subterranean scintillation telescope

1998 ◽  
Vol 87 (6) ◽  
pp. 1041-1045
Author(s):  
E. N. Alekseev ◽  
L. N. Alekseeva ◽  
V. N. Zakidyshev ◽  
V. Ya. Poddubnyi
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Low Energy ◽  
Neutrino Radiation ◽  
Energy Neutrino

FERMI LAT OBSERVATIONS OF GAMMA-RAY BURSTS

2009 ◽  
Vol 18 (10) ◽  
pp. 1545-1549
Author(s):  
◽  
F. LONGO
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Low Energy ◽  
Field Of View ◽  
Large Area ◽  
Energy Emission ◽  
Temporal Properties

We present the observations of Gamma-Ray Bursts (GRB) by the Fermi Large Area Telescope (LAT). In the first six months of the mission four GRB were detected at energies greater than 100 MeV by the LAT. The spectral and temporal properties of the three events detected within the LAT field of view, particulary with respect to the low-energy emission detected by the GBM, will be outlined.

scholarly journals Energy Spectra of Cosmic Gamma-Ray Bursts

1973 ◽  
Vol 185 ◽  
pp. L1 ◽  
Author(s):  
T. L. Cline ◽  
U. D. Desai ◽  
R. W. Klebesadel ◽  
I. B. Strong
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Energy Spectra
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