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Gamma-ray bursts (GRBs) are powered by ultra-relativistic jets. The launching sites of these jets are surrounded by dense media, which the jets must cross before they can accelerate and release the high energy emission. Interaction with the…

High Energy Astrophysical Phenomena · Physics 2024-10-22 Gal Birenbaum , Ramandeep Gill , Omer Bromberg , Paz Beniamini , Jonathan Granot

A certain degree of linear polarization has been measured in several GRB afterglows. More surprisingly, circular polarization has been recently measured in GRB121024A. For synchrotron emission, the polarization level depends on: (i) the…

High Energy Astrophysical Phenomena · Physics 2015-04-01 Lara Nava , Ehud Nakar , Tsvi Piran

Gamma-ray bursts (GRBs) are cosmic events occurring at large distances beyond our galaxy. They provide a unique opportunity to study electromagnetic patterns not seen elsewhere. When the collimated GRB outflow interacts with the outer…

A generic synchrotron external shock model is the widely preferred paradigm used to interpret the broad-band afterglow data of gamma-ray bursts (GRBs), including predicted observable signatures from a reverse shock which have been confirmed…

High Energy Astrophysical Phenomena · Physics 2015-09-23 He Gao , Peter Mészáros

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

Observations of the afterglows of gamma-ray bursts (GRBs) have revealed that they lie at cosmological distances, and so correspond to the release of an enormous amount of energy. The nature of the central engine that powers these events and…

Astrophysics · Physics 2008-11-26 W. Coburn , S. E. Boggs

Linear polarization measurements in the optical band show polarization degrees of a few percent at late times. Recently, polarization at sub-percent level was also detected in radio by ALMA, opening the window for multi-wavelength…

High Energy Astrophysical Phenomena · Physics 2021-07-21 Gal Birenbaum , Omer Bromberg

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

Polarization can serve as a probe of the radiation mechanism and magnetic field (MF) configuration in gamma-ray bursts (GRBs). In the case of constant MF, the synchrotron polarization in the prompt phase of GRBs has been widely studied. In…

High Energy Astrophysical Phenomena · Physics 2020-09-30 K. F. Cheng , X. H. Zhao , J. M. Bai

Over half a century from the discovery of gamma-ray bursts (GRBs), the dominant radiation mechanism responsible for their bright and highly variable prompt emission remains poorly understood. Spectral information alone has proven…

High Energy Astrophysical Phenomena · Physics 2021-10-20 Ramandeep Gill , Merlin Kole , Jonathan Granot

Gamma-ray bursts (GRBs) are extremely bright phenomena powered by relativistic jets arising from explosive events at cosmological distances. The nature of the jet and the configuration of the local magnetic fields are still unclear, with…

Observations by the {\RHESSI} satellite of large polarization of the prompt $\gamma$-ray emission from the Gamma Ray Burst GRB021206 \citep{coburn03} imply that the magnetic field coherence scale is larger than the size of the visible…

Astrophysics · Physics 2009-11-07 Maxim Lyutikov , V. I. Pariev , Roger Blandford

A formula for off-axis emissions from the beamed afterglow of GRBs in a synchrotron model is derived. The formula is applied to an inhomogeneous circumstellar matter obeying n proportional to 1/r**2 suggested for SN1998bw/GRB980425. The…

Astrophysics · Physics 2009-10-31 Takashi Nakamura

Gamma-ray bursts and their afterglows are thought to be produced by an ultrarelativistic jet. One of the most important open questions is the outflow composition: the energy may be carried out from the central source either as kinetic…

High Energy Astrophysical Phenomena · Physics 2016-06-01 Stefano Covino

Polarization measurements provide strong constraints on models for emission from rotation-powered pulsars. We present multiwavelength polarization predictions showing that measurements over a range of frequencies can be particularly…

High Energy Astrophysical Phenomena · Physics 2017-05-24 Alice K. Harding , Constantinos Kalapotharakos

Synchrotron circular polarization of a non-thermal power-law electron distribution in gamma-ray bursts (GRBs) has been studied. However, some numerical simulations have shown that the resulting distribution of electrons is a combination of…

High Energy Astrophysical Phenomena · Physics 2025-05-29 Kangfa Cheng , Jirong Mao , Xiaohong Zhao , Hongbang Liu , Zhegeng Chen , Gaojin Yu , Zhifu Chen

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

Among the large variety of astrophysical sources that we can observe, gamma-ray bursts (GRBs) are the most energetic of the whole Universe. The definition of a general picture describing the physics behind GRBs has always been a compelling…

High Energy Astrophysical Phenomena · Physics 2022-10-26 R. Brivio , S. Covino , P. D'Avanzo , K. Wiersema , J. R. Maund , M. G. Bernardini , S. Campana , A. Melandri

Linear and circular polarizations of gamma-ray bursts (GRBs) have been detected during recent years. We adopt a simplified model to investigate GRB polarization characteristics in this paper. A compressed two-dimensional turbulent slab…

High Energy Astrophysical Phenomena · Physics 2017-04-19 Jirong Mao , Jiancheng Wang

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