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Related papers: Temporal Evolution of Prompt GRB Polarization

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Modeling of gamma-ray burst (GRB) prompt emission spectra sometimes requires a (quasi-) thermal spectral component in addition to the Band function. In photospheric emission models, a prominent thermal component broadened by…

High Energy Astrophysical Phenomena · Physics 2020-09-30 Ramandeep Gill , Jonathan Granot , Paz Beniamini

The origin of prompt emission in GRBs is not yet well understood. The simplest and most popular model is Synchrotron, Self-Compton (SSC) emission produced by internal shocks inside an ultra-relativistic jet. However, recent observations of…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Houri Ziaeepour , Brian Gardner

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

Afterglows of gamma-ray bursts (GRBs) are emitted from expanding forward shocks, which are expected to have magnetic field much stronger than the interstellar field, although the origin of the field is a long-standing problem. Two field…

High Energy Astrophysical Phenomena · Physics 2023-02-08 Asuka Kuwata , Kenji Toma , Shigeo S. Kimura , Sara Tomita , Jiro Shimoda

The polarization of the prompt $\gamma$-ray emission has been measured in four bright gamma ray bursts (GRBs). It was nearly maximal in all cases, as predicted by the Cannonball (CB) model of GRBs long before the observations. These results…

Astrophysics · Physics 2007-05-23 Shlomo Dado , Arnon Dar , A. De Rujula

Time-resolved polarizations carry more physical information about the source of gamma-ray bursts (GRBs) than the time-integrated ones. Therefore, they give more strict constrains on the models of GRB prompt phase. Both time-resolved and…

High Energy Astrophysical Phenomena · Physics 2023-03-01 Rui-Rui Wu , Qing-Wen Tang , Mi-Xiang Lan

Synchrotron radiation and Compton scattering are widely accepted as the most likely emission mechanisms of some astrophysical phenomena, such as gamma-ray bursts (GRBs) and active galactic nuclei (AGNs). The measurement on polarization of…

High Energy Astrophysical Phenomena · Physics 2014-02-18 Zhe Chang , Hai-Nan Lin , Yunguo Jiang

Despite decades of polarization observations and high-significance polarized $\gamma$-ray, X-ray, optical, and radio emissions in gamma-ray bursts (GRBs) have been accumulating in dozens of cases, people have yet to find a consistent…

High Energy Astrophysical Phenomena · Physics 2022-08-09 Liang Li , She-Sheng Xue , Zi-Gao Dai

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

Context: Despite more than half a century of research, the dominant radiation mechanism of gamma-ray burst (GRB) prompt emission remains unsolved. Some progress has been made through the analyses of the observational spectra of Swift/BAT,…

High Energy Astrophysical Phenomena · Physics 2026-02-11 Yan-Zhi Meng , Shu-Qing Zhong , Jia-Hong Gu , Xin-Fei Li , Xiaozhou Zhao

The typical spectrum of the prompt emission of gamma-ray bursts (GRBs) indicates that the electron cooling is suppressed in spite of the strong magnetic field in the standard synchrotron model. Recent Particle-in-Cell simulations show that…

High Energy Astrophysical Phenomena · Physics 2022-07-07 Ryota Goto , Katsuaki Asano

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

The dominant radiation mechanism that powers the prompt $\gamma$-ray emission in gamma-ray bursts (GRBs) remains poorly understood. High quality, time- and energy-resolved linear polarization measurements of prompt $\gamma$-ray photons can…

High Energy Astrophysical Phenomena · Physics 2026-03-05 Ramandeep Gill , Jiang He , Jonathan Granot , Jian-Chao Sun , Shuang-Nan Zhang , Yuan-Hao Wang , Johannes Hulsman , Nicolas Produit , Shao-Lin Xiong

The magnetic field structure in GRB outflows is of great interest as it can provide valuable clues that can help pin down the mechanism responsible for the acceleration and collimation of GRB jets. The most promising way of probing it is…

Astrophysics · Physics 2009-11-10 Jonathan Granot , Gregory B. Taylor

Time-resolved linear polarization ($\Pi$) measurements of the prompt gamma-ray burst emission can reveal its dominant radiation mechanism. A widely considered mechanism is synchrotron radiation, for which linear polarization can be used to…

High Energy Astrophysical Phenomena · Physics 2024-01-01 Ramandeep Gill , Jonathan Granot

Despite decades of investigations, the physical mechanism that powers the bright prompt $\gamma$-ray emission from gamma-ray bursts (GRBs) is still not identified. One important observational clue that remains not properly interpreted so…

High Energy Astrophysical Phenomena · Physics 2016-07-13 Z. Lucas Uhm , Bing Zhang

A leading mechanism for producing cosmological gamma-ray bursts (GRBs) is via ultra-relativistic particles in an expanding fireball. The kinetic energy of the particles is converted into thermal energy in a forward shock and a reverse…

Astrophysics · Physics 2009-10-28 Re'em Sari , Ramesh Narayan , Tsvi Piran

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

We considered a model for the prompt phase of Gamma-Ray Burst (GRB) emission arising from a magnetized jet undergoing gradual energy dissipation due to magnetic reconnection. The dissipated magnetic energy is translated to bulk kinetic…

High Energy Astrophysical Phenomena · Physics 2017-05-03 Paz Beniamini , Dimitrios Giannios

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