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Related papers: Prompt GeV emission in the synchrotron self-Compto…

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We investigate the GeV emission from gamma-ray bursts (GRBs), using the results from the Energetic Gamma Ray Experimental Telescope (EGRET), and in view of the Gamma-ray Large Area Space Telescope (GLAST). Assuming that the conventional…

Astrophysics · Physics 2008-12-01 Shin'ichiro Ando , Ehud Nakar , Re'em Sari

Information on the spectral shape of prompt emission in gamma-ray bursts (GRB) is mostly available only at energies $\gtrsim10$ keV, where the main instruments for GRB detection are sensitive. The origin of this emission is still very…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Gor Oganesyan , Lara Nava , Giancarlo Ghirlanda , Andrea Melandri , Annalisa Celotti

The detection of the hyper-bright gamma-ray burst (GRB) 221009A enables us to explore the nature of GRB emission and the origin of very-high-energy (VHE) gamma-rays. We analyze the ${\it Fermi}$-LAT data and investigate GeV-TeV emission in…

High Energy Astrophysical Phenomena · Physics 2023-04-18 B. Theodore Zhang , Kohta Murase , Kunihito Ioka , Deheng Song , Chengchao Yuan , Péter Mészáros

We discuss the prompt emission of Gamma-Ray Bursts in different spectral energy bands. First, we suggest that a three-part synchrotron emission model is a good description of the ~20 keV - 1 MeV gamma-ray emission of GRBs. We show that this…

Astrophysics · Physics 2009-11-07 Nicole M. Lloyd-Ronning

The TeV emission detected in just five gamma-ray bursts (GRBs) is generally ascribed to the synchrotron emission or the synchrotron self-Compton process in the external forward shock. The brightest gamma-ray burst, GRB 221009A, with an…

High Energy Astrophysical Phenomena · Physics 2024-10-08 Zhi-Lin Chen , Da-Bin Lin , Guo-Yu Li , En-Wei Liang

In the framework of the internal shock scenario, we model the broadband prompt emission of gamma-ray bursts (GRBs) with emphasis on the GeV-TeV bands, utilizing Monte Carlo simulations that include various processes associated with…

Astrophysics · Physics 2009-06-23 Katsuaki Asano , Susumu Inoue

The emission mechanism of the gamma-ray bursts (GRBs) is still a matter of debates. The standard synchrotron energy spectrum of cooling electrons F_E ~ E^{-1/2} is much too soft to account for the majority of the observed spectral slopes.…

Astrophysics · Physics 2009-11-10 Boris E. Stern , Juri Poutanen

The synchrotron optical flash caught in GRB 990123 overlaps with the MeV radiation front, and the optical-emitting electrons must also produce GeV-TeV emission by inverse Compton scattering of MeV photons. The ultra-high-energy flash can be…

Astrophysics · Physics 2009-11-10 Andrei M. Beloborodov

Despite more than fifty years of gamma-ray burst (GRB) observations, several questions regarding the origin of the prompt emission, particularly at high energies, remain unresolved. We present a comprehensive analysis of 35 GRBs observed by…

High Energy Astrophysical Phenomena · Physics 2025-01-22 Samanta Macera , Biswajit Banerjee , Alessio Mei , Pawan Tiwari , Gor Oganesyan , Marica Branchesi

The high energy GeV emission of gamma-ray bursts (GRBs), detected by \emph{Fermi}/LAT, has a significantly different morphology compared to the lower energy MeV emission, detected by \emph{Fermi}/GBM. Though the late time GeV emission is…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Rupal Basak , A. R. Rao

The gamma-ray burst GRB 180720B is very peculiar. On one hand, some interesting features have been found by performing the detailed time-resolved spectral analysis in the prompt phase. First, the `flux-tracking' pattern is exhibited both…

High Energy Astrophysical Phenomena · Physics 2019-12-24 Ming-Ya Duan , Xiang-Gao Wang

The brightest Gamma-ray burst, GRB 221009A, has spurred numerous theoretical investigations, with particular attention paid to the origins of ultra-high energy TeV photons during the prompt phase. However, analyzing the mechanism of…

The observational diversity of optical emission, which coincides with prompt gamma-ray bursts (GRBs), has been discovered in the recent Swift era. We show that on the assumption of the synchrotron radiation for the observed energy range…

Astrophysics · Physics 2009-11-13 Hirotsugu Doi , Kentaro Takami , Ryo Yamazaki

We constrain the distance of the Gamma-Ray Burst (GRB) prompt emission site from the explosion centre, R, by determining the location of the electron's self absorption frequency in the GRB prompt optical-to-X/gamma-ray spectral energy…

High Energy Astrophysical Phenomena · Physics 2014-03-11 Rong-Feng Shen , Bing Zhang

We calculate the synchrotron self-Compton emission from internal shocks occurring in relativistic winds as a source of gamma-ray bursts, with allowance for self-absorption. For plausible model parameters most pulses within a Gamma-Ray Burst…

Astrophysics · Physics 2009-10-31 A. Panaitescu , P. Meszaros

The dominant component of the (100 MeV - 50 GeV) GRB emission detected by LAT starts with a delay relative to the prompt soft (sub-MeV) gamma-rays and lasts long after the soft component fades. This has lead to the intriguing suggestion…

High Energy Astrophysical Phenomena · Physics 2015-05-18 Tsvi Piran , Ehud Nakar

After more than 40 years from their discovery, the long-lasting tension between predictions and observations of GRBs prompt emission spectra starts to be solved. We found that the observed spectra can be produced by the synchrotron process,…

High Energy Astrophysical Phenomena · Physics 2020-03-25 Maria Edvige Ravasio

The most common progenitors of gamma-ray bursts (GRBs) are massive stars with strong stellar winds. We show that the GRB blast wave in the wind should emit a bright GeV flash. It is produced by inverse Compton cooling of the thermal plasma…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Andrei M. Beloborodov , Romain Hascoet , Indrek Vurm

Recently, very high-energy photons above 100 GeV were reported to be detected from GRB~190114C and GRB~180720B at, respectively, 100-1000 s and 10 hours after the burst. We model the available broad-band data of both GRBs with the…

High Energy Astrophysical Phenomena · Physics 2019-11-06 Xiang-Yu Wang , Ruo-Yu Liu , Hai-Ming Zhang , Shao-Qiang Xi , Bing Zhang

One of the principal results obtained by the Compton Gamma Ray Observatory relating to the study of gamma-ray bursts was the detection by the EGRET instrument of energetic ($>$100 MeV) photons from a handful of bright bursts. The most…

Astrophysics · Physics 2007-05-23 Matthew G. Baring
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