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Related papers: A key to the spectral variability of prompt GRBs

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We develop the theory of jitter radiation from GRB shocks containing small-scale magnetic fields and propagating at an angle with respect to the line of sight. We demonstrate that the spectra vary considerably: the low-energy photon index,…

Astrophysics · Physics 2009-11-13 Mikhail V. Medvedev

The origin of rapid spectral variability and certain spectral correlations of the prompt gamma-ray burst emission remains an intriguing question. The recently proposed theoretical model of the prompt emission is build upon unique spectral…

High Energy Astrophysical Phenomena · Physics 2009-08-24 Mikhail V. Medvedev , Sriharsha S. Pothapragada , Sarah J. Reynolds

A substantial fraction of prompt GRB spectra have soft spectral indexes exceeding the maximum allowed by the synchrotron model alpha_{max}=-2/3. Some spectra also exhibit very sharp break at E_p, inconsistent with the smooth synchrotron…

Astrophysics · Physics 2009-11-10 Mikhail V. Medvedev

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 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

(abridged)Prompt GRB emission is often interpreted as synchrotron radiation from high-energy electrons accelerated in internal shocks. Fast synchrotron cooling predicts that the photon index below the spectral peak is alpha=-3/2. This…

High Energy Astrophysical Phenomena · Physics 2015-05-19 F. Daigne , Z. Bosnjak , Guillaume Dubus

Detection of prompt emission by Swift-XRT provides a unique tool to study how the prompt spectrum of gamma-ray bursts (GRBs) extends down to the soft X-ray band. This energy band is particularly important for prompt emission studies, since…

High Energy Astrophysical Phenomena · Physics 2018-09-05 Gor Oganesyan , Lara Nava , Giancarlo Ghirlanda , Annalisa Celotti

The prompt emission of most gamma-ray bursts (GRBs) typically exhibits a non-thermal Band component. The synchrotron radiation in the popular internal shock model is generally put forward to explain such a non-thermal component. However,…

High Energy Astrophysical Phenomena · Physics 2021-09-17 Kai Wang , Zi-Gao Dai

The dominant radiation mechanism that produces the prompt emission in gamma-ray bursts (GRBs) remains a major open question. Spectral information alone has proven insufficient in elucidating its nature. Time-resolved linear polarization has…

High Energy Astrophysical Phenomena · Physics 2021-04-21 Ramandeep Gill , Jonathan Granot

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 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

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

The prompt emission of the long, smooth, and single-pulsed gamma-ray burst, GRB $\textit{141028A}$, is analyzed under the guise of an external shock model. First, we fit the $\gamma$-ray spectrum with a two-component photon model, namely…

High Energy Astrophysical Phenomena · Physics 2016-05-25 J. Michael Burgess , Damien Bégué , Felix Ryde , Nicola Omodei , Asaf Pe'er , J. L. Racusin , A. Cucchiara

Prompt {\gamma}-ray emissions from gamma-ray bursts (GRBs) exhibit a vast range of extremely complex temporal structures with a typical variability time-scale significantly short - as fast as milliseconds. This work aims to investigate the…

High Energy Astrophysical Phenomena · Physics 2011-09-28 G. Greco , R. Rosa , G. Beskin , S. Karpov , L. Romano , A. Guarnieri , C. Bartolini , R. Bedogni

A small fraction of GRBs with available data down to soft X-rays ($\sim0.5$ keV) have been shown to feature a spectral break in the low-energy part ($\sim1-10$ keV) of their prompt emission spectrum. The overall spectral shape is consistent…

High Energy Astrophysical Phenomena · Physics 2021-05-12 Ioulia Florou , Maria Petropoulou , Apostolos Mastichiadis

The shock model has successfully explained the observed behaviors of afterglows from long gamma-ray bursts (GRBs). Here we use it to investigate the so-called early afterglows from short GRBs, which arises from blast waves that are not…

Astrophysics · Physics 2009-11-10 Zhuo Li , Z. G. Dai , T. Lu

Fast spectral variability of gamma-ray burst emission is considered for a number of events seen by the Konus-Wind experiment. The variability manifests itself as a strong correlation between instantaneous energy flux $F$ and peak energy…

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 prompt emission phase of gamma-ray bursts (GRBs) exhibits two distinct patterns of the peak-energy ($E_p$) evolution, i.e., time-resolved spectral analyses of $\nu F_{\nu}$ spectra of broad pulses reveal (1) "hard-to-soft" and (2)…

High Energy Astrophysical Phenomena · Physics 2018-12-26 Z. Lucas Uhm , Bing Zhang , Judith Racusin

The prompt emission from GRBs is the brightest electromagnetic emission known yet it's origin is not understood. The flux density of individual prompt pulses of a GRB can be represented by an analytical expression derived assuming the…

High Energy Astrophysical Phenomena · Physics 2015-05-14 R. Willingale , F. Genet , J. Granot , P. T. O'Brien
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