Related papers: Circular Polarization from Gamma-ray Burst Aftergl…
The late-time optical/radio afterglows of $\gamma$-ray bursts (GRBs) are believed to be synchrotron emission of electrons accelerated in relativistic collisionless shocks propagating in the ambient medium of the sources. However, the…
The afterglows of gamma-ray bursts are non-thermal electron synchrotron emissions from relativistic shocks. The origin of strong magnetic field in the emission region remains elusive, and two field amplification mechanisms via the plasma…
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…
We report that the optical polarization in the afterglow of GRB 091208B is measured at t = 149 - 706 s after the burst trigger, and the polarization degree is P = 10.4% +/- 2.5%. The optical light curve at this time shows a power-law decay…
Gamma-ray burst (GRB) afterglow emission is believed to be produced by synchrotron emission of electrons accelerated to high energy by a relativistic collisionless shock propagating into a weakly magnetized plasma. Afterglow observations…
Gamma-Ray Burst afterglow polarization measurements, in spite of their intrinsic difficulties, have been carried out for a number of events that begins to be adequate to draw some general statistical conclusions. Although the presence of…
Linear polarization has been measured in several GRB afterglows. After a few days, polarization arises from the forward shock emission which depends on the post-shock magnetic field. The latter can originate both from compression of…
We report the detection of significant polarization in the optical afterglow of GRB990712 on three instances 0.44, 0.70 and 1.45 days after the gamma-ray burst, with (P, theta) being (2.9% +- 0.4%, 121.1 degr +- 3.5 degr), (1.2% +- 0.4%,…
We show that the Weibel or currente filamentation instability can lead to the emission of circularly polarized radiation. Using particle-in-cell (PIC) simulations and a radiation post-processing numerical algorithm, we demonstrate that the…
We report the first detection of radio polarization of a GRB afterglow with the first intensive combined use of telescopes in the millimeter and submillimeter ranges for GRB171205A. The linear polarization degree in the millimeter band at…
Linear polarization have been observed in both the prompt phase and afterglow of some bright gamma-ray bursts (GRBs). Polarization in the prompt phase spans a wide range, and may be as high as $\gtrsim 50\%$. In the afterglow phase,…
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…
A possible birefringence effect that arises in quantum gravity leads to a frequency-dependent rotation of the polarization angle of linearly polarized emission from distant sources. Here we use the UV/optical polarization data of the…
Models for gamma-ray burst afterglows envisage an hyper-relativistic fireball that is decelerated in the ambient medium around the explosion site. This interaction produces a shock wave which amplifies the magnetic field and accelerates…
The early optical afterglow emission of several gamma-ray bursts (GRBs) shows a high linear polarization degree (PD) of tens of percent, suggesting an ordered magnetic field in the emission region. The light curves are consistent with being…
A relativistic electron-positron beam propagating through a magnetized electron-ion plasma is shown to generate both circularly and linearly polarized synchrotron radiation. The degrees of circular and linear polarizations depend both on…
We report polarization measurements and photometry for the optical afterglow of the gamma-ray burst GRB 020405. We measured a highly significant 9.9% polarization (in V band) 1.3 days after the burst and argue that it is intrinsic to the…
We present a catalog of early-time (~10^2-10^4s) photometry and polarimetry of all Gamma-Ray Burst (GRB) optical afterglows observed with RINGO2 imaging polarimeter on the Liverpool Telescope. For the 19 optical afterglows observed, the…
Gamma-ray bursts (GRBs) are the most luminous transients in the universe and are utilized as probes of early stars, gravitational wave counterparts, and collisionless shock physics. In spite of studies on polarimetry of GRBs in individual…
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…