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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

Evidence of polarized $\gamma$-ray emission ($>$ 50 keV) from Gamma-Ray Bursts (GRBs) has been accumulated in recent years. Measurements have been reported with levels in the range of 30-80\%, typically with limited statistical…

High Energy Astrophysical Phenomena · Physics 2017-02-22 Mark L. McConnell

The physical processes of the gamma-ray emission and particle acceleration during the prompt phase in GRBs are still unsettled. In order to perform an unambiguous physical modelling of observations, a clear identification of the emission…

High Energy Astrophysical Phenomena · Physics 2022-06-29 Felix Ryde , Shabnam Iyyani , Björn Ahlgren , Asaf Peer , Vidushi Sharma , Christoffer Lundman , Magnus Axelsson

The mechanism responsible for the prompt gamma-ray emission of a gamma-ray burst continues to remain an enigma. The detailed analysis of the spectrum of GRB 131014A observed by the $Fermi$ gamma ray burst monitor and Large Area Telescope…

High Energy Astrophysical Phenomena · Physics 2025-09-18 Pragyan Pratim Bordoloi , Shabnam Iyyani

The gamma-ray burst (GRB) 060218/SN 2006aj is a peculiar event, with the second lowest redshift, low luminosity, long duration, chromatic lightcurve features, and in particular, the presence of a thermal component in the X-ray and…

Astrophysics · Physics 2007-05-23 Z. G. Dai , Bing Zhang , E. W. Liang

Aims. With the accumulation of polarization data in the gamma-ray burst (GRB) prompt phase, polarization models can be tested. Methods. We predicted the time-integrated polarizations of 37 GRBs with polarization observation. We used their…

High Energy Astrophysical Phenomena · Physics 2023-02-22 R. Y. Guan , M. X. Lan

There is no complete description of the emission physics during the prompt phase in gamma-ray bursts. Spectral analyses, however, indicate that many spectra are narrower than what is expected for non-thermal emission models. Here, we…

High Energy Astrophysical Phenomena · Physics 2020-05-06 Zeynep Acuner , Felix Ryde , Asaf Pe'er , Daniel Mortlock , Björn Ahlgren

Gamma-ray bursts are the most energetic electromagnetic sources in the Universe. Their prompt gamma-ray radiation corresponds to an energy release of 1E42-1E47J. Fifty years after their discovery and several dedicated space-based…

High Energy Astrophysical Phenomena · Physics 2019-10-22 J. Michael Burgess , Damien Bégué , Ana Bacelj , Dimitrios Giannios , Francesco Berlato , Jochen Greiner

Internal shocks are a leading candidate for the dissipation mechanism that powers the prompt $\gamma$-ray emission in gamma-ray bursts (GRBs). In this scenario a compact central source produces an ultra-relativistic outflow with varying…

High Energy Astrophysical Phenomena · Physics 2023-12-25 Sk. Minhajur Rahaman , Jonathan Granot , Paz Beniamini

Quasi-thermal Comptonization is an attractive alternative to the synchrotron process to explain the spectra of GRBs, even if we maintain other important properties of the internal shock scenario, implying a compact emitting region and an…

Astrophysics · Physics 2009-10-31 Gabriele Ghisellini , Annalisa Celotti

Besides light curves and spectra, polarization provides a different powerful tool of studying the $\gamma-$ray burst (GRB) prompt phase. Compared with the time-integrated and energy-integrated polarization, time-resolved and energy-resolved…

High Energy Astrophysical Phenomena · Physics 2020-04-15 Mi-Xiang Lan , Zi-Gao Dai

Relativistic electrons accelerated by both the first-order and the second-order Fermi accelerations in some synchrotron sources have a hybrid shape of thermal and nonthermal energy distribution. This particle acceleration result is…

High Energy Astrophysical Phenomena · Physics 2018-03-14 Jirong Mao , Jiancheng Wang

In the external shock model, gamma-ray burst (GRB) emissions are produced by the energization and deceleration of a thin relativistic blast wave due to its interactions with the circumburst medium (CBM). We study the physical properties of…

Astrophysics · Physics 2009-10-31 Charles D. Dermer , Markus Boettcher , J. Chiang

The photospheric emission in the prompt phase is the natural prediction of the original fireball model for gamma-ray burst (GRB) due to the large optical depth ($\tau >1$) at the base of the outflow, which is supported by the quasi-thermal…

High Energy Astrophysical Phenomena · Physics 2021-12-02 Yan-Zhi Meng , Jin-Jun Geng , Xue-Feng Wu

The electron energy distribution index, p, is a fundamental parameter of the synchrotron emission from a range of astronomical sources. Here we examine one such source of synchrotron emission, Gamma-Ray Burst afterglows observed by the…

High Energy Astrophysical Phenomena · Physics 2010-05-28 P. A. Curran , P. A. Evans , M. de Pasquale , M. J. Page , A. J. van der Horst

The MeV spectral peak of gamma-ray bursts (GRBs) is best explained as photospheric emission from a dissipative relativistic jet. The observed non-blackbody spectrum shows that sub-photospheric dissipation involves both thermal plasma…

High Energy Astrophysical Phenomena · Physics 2016-11-07 Christoffer Lundman , Indrek Vurm , Andrei M. Beloborodov

We propose a model for the spectral formation of Gamma Ray Burst (GRB) prompt emission, where the phenomenological Band's function is usually applied to describe the GRB prompt emission. We suggest that the GRB prompt emission is mainly a…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Lev Titarchuk , Ruben Farinelli , Filippo Frontera , Lorenzo Amati

Abridged.-- We demonstrate that the radiation emitted by ultrarelativistic electrons in highly nonuniform, small-scale magnetic fields is different from synchrotron radiation if the electron's transverse deflections in these fields are much…

Astrophysics · Physics 2008-11-26 Mikhail V. Medvedev

Knowledge of the bulk Lorentz factor $\Gamma_{0}$ of GRBs allows us to compute their comoving frame properties shedding light on their physics. Upon collisions with the circumburst matter, the fireball of a GRB starts to decelerate,…

High Energy Astrophysical Phenomena · Physics 2018-01-31 G. Ghirlanda , F. Nappo , G. Ghisellini , A. Melandri , G. Marcarini , L. Nava , O. S. Salafia , S. Campana , R. Salvaterra

The energy dissipation mechanism within Gamma-Ray Burst (GRB) outflows, driving their extremely luminous prompt $\gamma$-ray emission is still uncertain. The leading candidates are internal shocks and magnetic reconnection. While the…

High Energy Astrophysical Phenomena · Physics 2016-05-13 Paz Beniamini , Jonathan Granot