相关论文: Numerical simulations of polarisation in gamma-ray…
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…
We study the ensemble of linear polarization measurement in the optical afterglows of long-duration gamma-ray bursts. We assume a non sideways-expanding top-hat jet geometry and use the relatively large number of measurements under the…
Linear polarization at the level of $\sim 1-3%$ has by now been measured in several gamma-ray burst afterglows. Whereas the degree of polarization, $P$, was found to vary in some sources, the position angle, $\theta_p$, was roughly constant…
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…
GRB afterglow polarization is discussed. We find an observable, up to 10%, polarization, if the magnetic field coherence length grows at about the speed of light after the field is generated at the shock front. Detection of a polarized…
As we further our studies on Gamma-ray bursts (GRBs), both on theoretical models and observational tools, more and more options begin to open for exploration of its physical properties. As transient events primarily dominated by synchrotron…
Polarisation measurements of gamma-ray burst afterglows provide a powerful tool for probing the structure of relativistic jets. In this study, we revisit polarisation signals observed in gamma-ray burst afterglows, focusing on the effects…
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 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…
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…
We present ALMA 97.5 GHz total intensity and linear polarization observations of the mm-band afterglow of GRB 190114C spanning 2.2 to 5.2 hours after the burst. We detect linear polarization at the $\approx 5\,\sigma$ level, decreasing from…
We present polarimetric observations of the afterglow of gamma-ray burst (GRB) 021004, obtained with the Nordic Optical Telescope (NOT) and the Very Large Telescope (VLT) between 8 and 17 hours after the burst. Comparison among the…
Polarization measurements of gamma-ray burst (GRB) afterglows are a promising means of probing the structure, geometry, and magnetic composition of relativistic GRB jets. However, a precise treatment of instrumental calibration is vital for…
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,…
The recently detected linear polarization in the optical lightcurve of GRB 990510 renewed the interest on how polarization can be produced in gamma-ray burst fireballs. Here we present a model based on the assumption that we are seeing a…
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…
Gamma-ray burst afterglows arise from relativistic collisionless shocks in which the postshock tangled magnetic field $\vec{B}$ is produced by the two-stream and/or Weibel instabilities on plasma skin-depth scales $(c/\omega_p)$. The field…
Multi-wave band synchrotron linear polarization of gamma-ray burst (GRB) afterglows is studied under the assumption of an anisotropic turbulent magnetic field with a coherence length of the plasma skin-depth scale in the downstream of…
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…
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…