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Related papers: An External Shock Origin of GRB $\textit{141028A}$

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The origin of prompt emission in $\gamma$-ray bursts (GRBs) is highly debated topic. The observed spectra are supposed to play a crucial role in constraining the location of the emitting region, the strength of the magnetic field and the…

High Energy Astrophysical Phenomena · Physics 2020-06-26 Gor Oganesyan

The prompt optical emission that arrives with gamma-rays from a cosmic gamma-ray burst (GRB) is a signature of the engine powering the burst, the properties of the ultra-relativistic ejecta of the explosion, and the ejecta's interactions…

The physical origin of gamma-ray burst (GRB) prompt emission (photosphere or synchrotron) is still subject to debate after five decades. Here, firstly we find that many observed characteristics of 15 long GRBs, which have the highest prompt…

High Energy Astrophysical Phenomena · Physics 2022-12-13 Yan-Zhi Meng

The TeV observations of GRB~221009A provided us with a unique opportunity to analyze the contemporaneous phase in which both prompt and afterglow emissions are seen simultaneously. To describe this initial phase of Gamma-Ray Burst…

High Energy Astrophysical Phenomena · Physics 2023-12-05 Evgeny Derishev , Tsvi Piran

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

The Swift satellite has enabled us to follow the evolution of gamma-ray burst (GRB) fireballs from the prompt gamma-ray emission to the afterglow phase. The early x-ray and optical data obtained by telescopes aboard the Swift satellite show…

The taxonomy of optical emission detected during the critical first few minutes after the onset of a gamma-ray burst (GRB) defines two broad classes: prompt optical emission correlated with prompt gamma-ray emission, and early optical…

Four years after the launch the Swift satellite the nature of the Gamma Ray Bursts (GRBs) broadband afterglow behaviour is still an open issue ad the standard external shock fireball models cannot easily explain the puzzling combined…

High Energy Astrophysical Phenomena · Physics 2009-08-05 M. Nardini , G. Ghisellini , G. Ghirlanda , A. Celotti

Discerning the radiative dissipation mechanism for prompt emission in Gamma-Ray Bursts (GRBs) requires detailed spectroscopic modeling that straddles the $\nu F_{\nu}$ peak in the 100 keV - 1 MeV range. Historically, empirical fits such as…

An intriguing hypothesis, that there exists a decaying X-ray emission component before the GRB trigger, has been suggested in order to explain the shallow decay phase of the X-ray afterglow detected in many Swift GRBs. If this "prior…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Tesla Birnbaum , Bing Zhang , Bin-Bin Zhang , En-Wei Liang

The prompt GRB emission is thought to arise from electrons accelerated in internal shocks propagating within a highly relativistic outflow. The launch of Fermi offers the prospect of observations with unprecedented sensitivity in…

Astrophysics · Physics 2015-05-13 Z. Bosnjak , F. Daigne , G. Dubus

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 principal paradigm for gamma-ray bursts (GRBs) suggests that the prompt transient gamma-ray signal arises from multiple shocks internal to the relativistic expansion. This paper explores how GRB prompt emission spectra can constrain…

High Energy Astrophysical Phenomena · Physics 2009-06-25 Matthew G. Baring

The origin of prompt emission from gamma ray bursts remains to be an open question. Correlated prompt optical and gamma-ray emission observed in a handful of GRBs strongly suggests a common emission region, but failure to adequately fit the…

High Energy Astrophysical Phenomena · Physics 2016-12-21 S. Guiriec , C. Kouveliotou , D. H. Hartmann , J. Granot , K. Asano , P. Meszaros , R. Gill , N. Gehrels , J. McEnery

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

Long gamma-ray bursts (GRBs), which signify the end-life collapsing of very massive stars, are produced by extremely relativistic jets colliding into circumstellar medium. Huge energy is released both in the first few seconds, namely the…

Ultra-relativistic motion and efficient conversion of kinetic energy to radiation are required by gamma-ray burst (GRB) observations, yet they are difficult to simultaneously achieve. Three leading mechanisms have been proposed to explain…

High Energy Astrophysical Phenomena · Physics 2016-04-06 Damien Bégué , J. Michael Burgess

The prompt emission of low-luminosity gamma-ray bursts (llGRBs) indicates that these events originate from a relativistic shock breakout. In this case we can estimate, based on the properties of the prompt emission, the energy distribution…

High Energy Astrophysical Phenomena · Physics 2015-05-12 Rodolfo Barniol Duran , Ehud Nakar , Tsvi Piran , Re'em Sari

The recent launches of the Einstein Probe (EP) and the Space Variable Objects Monitor (SVOM) mission have led to the detection of a growing number of long GRBs with significant, early soft X-ray flux during their gamma-ray emission,…

High Energy Astrophysical Phenomena · Physics 2025-10-21 Ziming Wang , Chenyu Wang , He Gao , Hua Feng , An Li , Lin Lin , Songyu Shen