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As is well-known, the requirement that gamma ray bursts (GRB's) be optically thin to high energy photons yields a lower limit on the Lorentz factor (\gamma) of the expansion. In this paper, we provide a simple derivation of the lower limit…

Astrophysics · Physics 2009-10-31 Yoram Lithwick , Re'em Sari

In this paper, we study the correlation between isotropic energy and duration of gamma-ray bursts (GRBs) for the first time. The correlation is found to be $T_d \propto {E_{iso}}^{0.34\pm 0.03}$ from the {\em Swift} GRB sample. After…

High Energy Astrophysical Phenomena · Physics 2018-12-26 Z. L. Tu , F. Y. Wang

We present a multi-variable regression analysis to several observable quantities for a sample of 15 gamma-ray bursts (GRBs). The observables used in the analysis includes the isotropic gamma-ray energy (E_{gamma,iso}), the peak energy of…

Astrophysics · Physics 2008-11-26 Enwei Liang , Bing Zhang

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 correlations between the rest frame peak of the EF_E spectrum of GRBs Epeak and their isotropic energy (E_iso) or luminosity (L_iso) could have several implications for the understanding of the GRB prompt emission. These correlations…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Giancarlo Ghirlanda

We introduce a new model of gamma ray burst (GRB) that explains its observed prompt signals, namely, its primary quasi-thermal spectrum and high energy tail. This mechanism can be applied to either assumption of GRB progenitor: coalescence…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Pisin Chen , Toshi Tajima , Yoshi Takahashi

The effect of quantum gravity can bring a tiny light speed variation which is detectable through energetic photons propagating from gamma ray bursts (GRBs) to an observer such as the space observatory. Through an analysis of the energetic…

High Energy Physics - Phenomenology · Physics 2016-09-07 Haowei Xu , Bo-Qiang Ma

We collected the information of 304 gamma-ray bursts (GRBs) from the literature, and analyzed the correlations among the host galaxy offsets (the distance from the site of the GRB to the center of its host galaxy), $T_{\rm 90,i}$ (the…

High Energy Astrophysical Phenomena · Physics 2019-03-01 Fei-Fei Wang , Yuan-Chuan Zou , Yu Liu , Bin Liao , Reetanjali Moharana

A long and intense gamma-ray burst (GRB) was detected by INTEGRAL on July 11 2012 with a duration of ~115s and fluence of 2.8x10^-4 erg cm^-2 in the 20 keV-8 MeV energy range. GRB 120711A was at z~1.405 and produced soft gamma-ray emission…

We determine the basic physical characteristics of eight Gamma-Ray Bursts -- 980519, 990123, 990510, 991028, 991216, 000301c, 000926 and 010222 -- by modelling the broadband emission of their afterglows. We find that the burst kinetic…

Astrophysics · Physics 2009-11-07 A. Panaitescu , P. Kumar

Previous studies have considered synchrotron as the emission mechanism for prompt Gamma-Ray Bursts (GRBs). These works have shown that the electrons must cool on a timescale comparable to the dynamic time at the source in order to satisfy…

High Energy Astrophysical Phenomena · Physics 2018-02-28 Paz Beniamini , Rodolfo Barniol Duran , Dimitrios Giannios

We calculate the prompt x-ray emission as a function of viewing angle for beamed Gamma-Ray Burst (GRB) sources. Prompt x-rays are inevitable due to the less highly blueshifted photons emitted at angles greater than 1/gamma relative to the…

Astrophysics · Physics 2009-10-31 Eric Woods , Abraham Loeb

We use 1+1/2 dimensional particle-in-cell plasma simulations to study the interaction of a relativistic, strongly magnetized wind with an ambient medium. Such an interaction is a plausible mechanism which leads to generation of cosmological…

Astrophysics · Physics 2009-10-31 M. V. Smolsky , V. V. Usov

It has been widely recognized that gamma-ray burst (GRB) afterglows arise from interactions between GRB outflow and circumburst medium, while their evolution follows the behaviors of relativistic shock waves. Assuming the distribution of…

High Energy Astrophysical Phenomena · Physics 2022-03-17 Bo Zhang , Liang-Duan Liu , Tian-Rui Sun , Fen Lyu , Xue-Feng Wu

Gamma-Ray Bursts (GRBs) - short bursts of 100-1MeV photons arriving from random directions in the sky are probably the most relativistic objects discovered so far. Still, somehow they did not attract the attention of the relativistic…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Tsvi Piran

In the standard scenario of the fireball model of gamma-ray bursts(GRBs), the huge initial energy release produces a relativistic blast wave expanding into the external medium and a reverse shock moving into and heating the fireball ejecta.…

Astrophysics · Physics 2009-10-31 X. Y. Wang , Z. G. Dai , T. Lu

The existence of strong correlation between the peak luminosity (and/or bolometric energetics) of Gamma Ray Bursts (GRB) is one of the most intrigue problem of GRB physics. This correlation is not yet understood. Here we demonstrate that…

Astrophysics · Physics 2007-08-22 M. Yu. Piotrovich , Yu. N. Gnedin , T. M. Natsvlishvili

It is proposed that the gamma ray burst photons near the peak of the spectrum at several hundred KeV are produced on very compact scales, where photon production is limited by blackbody effects and/or the requirement of energetic quanta…

Astrophysics · Physics 2009-10-31 D. Eichler , A. Levinson

Early X-ray emission of Gamma-Ray Bursts (GRBs) traces the transition between the prompt emission and the afterglow radiation, and its rapid flux decline is often interpreted as the tail of the prompt emission. As such, it can offer…

High Energy Astrophysical Phenomena · Physics 2026-04-08 Annarita Ierardi , Gor Oganesyan , Stefano Ascenzi , Marica Branchesi , Biswajit Banerjee , Samuele Ronchini

We present the results of a comprehensive study of the luminosity function, energetics, prompt gamma-ray correlations, and classification methodology of short-hard and long-soft GRBs (SGRBs and LGRBs), based on observational data in the…

High Energy Astrophysical Phenomena · Physics 2015-08-06 Amir Shahmoradi , Robert J. Nemiroff