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Related papers: Afterglow Polarization from Off-Axis GRB Jets

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A large-scale ordered magnetic field plays a very important role in the formation and acceleration of a gamma-ray burst (GRB) jet. During the GRB prompt phase, some dissipation processes may happen and disturb the magnetic field, making the…

High Energy Astrophysical Phenomena · Physics 2019-01-23 Mi-Xiang Lan , Jin-Jun Geng , Xue-Feng Wu , Zi-Gao Dai

Despite being hard to measure, GRB prompt $\gamma$-ray emission polarization is a valuable probe of the dominant emission mechanism and the outflow's composition and angular structure. During the prompt emission the outflow is…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Ramandeep Gill , Jonathan Granot , Pawan Kumar

Models for gamma-ray burst afterglow dynamics and synchrotron spectra are known to exhibit various scale invariances, owing to the scale-free nature of fluid dynamics and the power-law shape of synchrotron spectra. Since GRB 170817A,…

High Energy Astrophysical Phenomena · Physics 2024-04-26 Hendrik van Eerten , Geoffrey Ryan

We numerically compute light and polarisation curves of gamma-ray burst afterglows for various configurations of the jet luminosity structure and for different dynamical evolutions. We especially consider the standard homogeneous ``top…

Astrophysics · Physics 2009-11-10 Elena M. Rossi , D. Lazzati , Jay D. Salmonson , G. Ghisellini

We report 31 polarimetric observations of the afterglow of GRB 030329 with high signal-to-noise and high sampling frequency. We establish the polarization light curve, detect sustained polarization at the percent level, and find significant…

Synchrotron is considered the dominant emission mechanism in the production of gamma-ray burst photons in the prompt as well as in the afterglow phase. Polarization is a characteristic feature of synchrotron and its study can reveal a…

Astrophysics · Physics 2009-11-11 Davide Lazzati

Particle acceleration is expected to be different between relativistic and non-relativistic collisionless shocks. We show that electromagnetic counterparts to gravitational waves (GWs), gamma-ray burst (GRB) afterglows, are ideal targets…

High Energy Astrophysical Phenomena · Physics 2022-11-16 Kazuya Takahashi , Kunihito Ioka , Yutaka Ohira , Hendrik J. van Eerten

We report the optical polarization of a gamma ray burst (GRB) afterglow, obtained 203 seconds after the initial burst of gamma rays from GRB 060418, using a ring polarimeter on the robotic Liverpool Telescope. Our robust (2-sigma) upper…

Energy injection into the external shock system that generates the afterglow to a gamma-ray burst (GRB) can result in a re-brightening of the emission. Here we investigate the off-axis view of a re-brightened refreshed shock afterglow. We…

High Energy Astrophysical Phenomena · Physics 2020-08-26 Gavin P. Lamb , Andrew J. Levan , Nial R. Tanvir

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

The X-ray afterglows of almost one half of gamma-ray bursts have been discovered to have a shallow decay phase by the {\em Swift} satellite, whose origin remains mysterious. Two main models have been proposed to explain this phase,…

High Energy Astrophysical Phenomena · Physics 2016-08-03 Mi-Xiang Lan , Xue-Feng Wu , Zi-Gao Dai

The dynamics of GRB jets during the afterglow phase is most reliably and accurately modelled using hydrodynamic simulations. All published simulations, however, have considered only a uniform external medium, while a stratified external…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Fabio De Colle , Enrico Ramirez-Ruiz , Jonathan Granot , Diego Lopez-Camara

Follow-up observations of large numbers of gamma-ray burst (GRB) afterglows, facilitated by the Swift satellite, have produced a large sample of spectral energy distributions and light curves, from which the basic micro- and macrophysical…

High Energy Astrophysical Phenomena · Physics 2015-06-15 K. Wiersema

We present a possible theoretical interpretation of the observed afterglow emission of long gamma-ray burst GRB 080710. While its prompt GRB emission properties are normal, the afterglow light curves in the optical and infrared bands are…

High Energy Astrophysical Phenomena · Physics 2024-01-10 Kaori Obayashi , Ayumu Toriyama , Mayu Murakoshi , Yuri Sato , Shuta J. Tanaka , Takanori Sakamoto , Ryo Yamazaki

Starting as highly relativistic collimated jets, gamma-ray burst outflows gradually decelerate and become non-relativistic spherical blast waves. Although detailed analytical solutions describing the afterglow emission received by an…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Hendrik van Eerten , Weiqun Zhang , Andrew MacFadyen

A comprehensive understanding of Gamma Ray Bursts (GRBs) has been elusive due to the variety of questions surrounding the radiation mechanism at play in these events. Polarization measurements of GRBs can heavily constrain the relevant…

High Energy Astrophysical Phenomena · Physics 2020-07-01 Tyler Parsotan , Diego Lopez-Camara , Davide Lazzati

We discuss jet dynamics for narrow and wide gamma-ray burst (GRB) afterglow jets and the observational implications of numerical simulations of relativistic jets in two dimensions. We confirm earlier numerical results that sideways…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Hendrik J. van Eerten , Andrew I. MacFadyen

Synchrotron emission polarization is very sensitive to the magnetic field configuration. Recently, polarization of synchrotron emission with a mixed (SM) magnetic field in Gamma-ray burst (GRB) afterglow phase had been developed. Here, we…

High Energy Astrophysical Phenomena · Physics 2021-05-05 Mi-Xiang Lan , Xue-Feng Wu , Zi-Gao Dai

Some progenitor models of gamma-ray bursts (GRBs) (e.g., collapsars) may produce anisotropic jets in which the energy per unit solid angle is a power-law function of the angle ($\propto\theta^{-k}$). We calculate light curves and spectra…

Astrophysics · Physics 2009-10-31 Z. G. Dai , L. J. Gou

We study the morphology of gamma-ray burst (GRB) afterglows viewed off-axis using a simplified analytical model. We consider steep jets, which are expected to be the most common type. These jets, characterized by steep lateral gradients in…

High Energy Astrophysical Phenomena · Physics 2025-04-18 Ernazar Abdikamalov , Paz Beniamini