Modeling the Linear Polarization of GRB Afterglows Across the Electromagnetic Spectrum
arXiv:2105.04574 · doi:10.1093/mnras/stab1936
Abstract
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 polarimetry and stressing the importance of properly modeling polarization in GRB afterglows across the EM spectrum. We introduce a numerical tool that can calculate the polarization from relativistically moving surfaces by discretizing them to small patches of uniform magnetic field, calculating the polarized emission from each cell assuming synchrotron radiation and summing it to obtain the total degree of polarization. We apply this tool to afterglow shocks with random magnetic fields confined to the shock plane, considering electron radiative cooling. We analyze the observed polarization curves in several wavelengths above the cooling frequency and below the minimal synchrotron frequency and point to the characteristic differences between them. We present a method to constrain the jet opening angle and the viewing angle within the context of our model. Applying it to GRB 021004 we obtain angles of 10 and 8 degrees respectively and conclude that a non-negligible component of radial magnetic field is required to explain the 1% polarization level observed 3.5 days after the burst.
arXiv comment14 pages, 10 figures
References in corpus (36)
- Spectra and Light Curves of Gamma-Ray Burst Afterglows
- Generation of Magnetic Fields in the Relativistic Shock of Gamma-Ray-Burst Sources
- Viewing Angle and Environment Effects in GRB: Sources of Afterglow Diversity
- GRB after-glow: Supporting the cosmological fireball model, constraining parameters, and making predictions
- Radio Transients from Gamma-Ray Bursters
- Gamma-Ray Burst Afterglow: Polarization and Analytic Light Curves
- Images and Spectra From the Interior of a Relativistic Fireball
- Hydrodynamics of Relativistic Fireballs
- Linear Polarization and Proper Motion in The Afterglow of Beamed GRBs
- Gamma-ray burst after-glow: Confirming the cosmological fireball model
- Long-time evolution of magnetic fields in relativistic GRB shocks
- Hydrodynamics of a Relativistic Fireball: the Complete Evolution
- Two Populations and Models of Gamma Ray Bursts
- Linear Polarization in Gamma-Ray Bursts: The Case for an Ordered Magnetic Field
- Polarization lightcurves and position angle variation of beamed gamma-ray bursts
- The polarisation of afterglow emission reveals GRB jet structure
- The Most Probable Cause for the High Gamma-Ray Polarization in GRB 021206
- The discovery of polarization in the afterglow of GRB 990510 with the ESO Very Large Telescope
- The Observed Size and Shape of GRB Afterglow
- Evolution of the polarization of the optical afterglow of the gamma-ray burst GRB 030329
- Optical Photometry of GRB 021004: The First Month
- Detailed optical and near-infrared polarimetry, spectroscopy and broadband photometry of the afterglow of GRB 091018: Polarisation evolution
- The Strongly Polarized Afterglow of GRB 020405
- Constraining the magnetic field structure in collisionless relativistic shocks with a radio afterglow polarization upper limit in GW170817
- GRB990712: First Indication of Polarization Variability in a Gamma-ray Burst Afterglow
- ALMA Detection of a Linearly Polarized Reverse Shock in GRB 190114C
- Variable polarization in the optical afterglow of GRB 021004
- Linear polarization in gamma-ray burst prompt emission
- Polarization and light curve variability: the "patchy shell" model
- Polarization Evolution of the GRB 020405 Afterglow
- First Detection of Radio Linear Polarization in a Gamma Ray Burst Afterglow
- Prospects for multiwavelength polarization observations of GRB afterglows and the case GRB 030329
- Multi-Wave band Synchrotron Polarization of Gamma-Ray Burst Afterglows
- Analytic Expressions for the Surface Brightness Profile of GRB Afterglow Images
- Planck intermediate results. XV. A study of anomalous microwave emission in Galactic clouds
- Polarization of Gamma--Ray Burst Optical and Near-Infrared Afterglows
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- Afterglow Linear Polarization Signatures from Steep GRB Jets: Implications for Orphan Afterglows