A new method infers inhomogeneities and asymmetries in high-energy transients from their radio synchrotron self-absorption spectra and demonstrates it on SN 2016coi and AT2018cow.
First Detection of Faraday Rotation in a Gamma-Ray Burst Afterglow: Low Polarization and High Rotation Measure in GRB 260310A Reveal Jet Magnetic Structure and Environment
4 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
We report the detection of linear polarization in the radio afterglow of GRB 260310A, representing the first centimeter-wavelength polarization detection of a gamma-ray burst (GRB) afterglow and the first measurement of Faraday rotation in a GRB environment. We detect linearly polarized emission across $11-25$ GHz, with a polarization fraction decreasing monotonically from $(3.18 \pm 0.18)\%$ at 25 GHz to $(0.69 \pm 0.22)\%$ at 11 GHz. Interpreting the radio data as emission from a reverse shock in a structured, relativistic jet, the observed depolarization toward lower frequencies is consistent with suppression by synchrotron self-absorption, while the low observed polarization at high frequencies relative to the theoretical maximum suggests a patchy magnetic field in the jet with a coherence scale, $\theta_{\rm B}\approx10^{-2}$ rad. We identify a frequency-dependent rotation of the polarization angle consistent with Faraday rotation, with a rotation measure of ${\rm RM} = -(8300 \pm 90)~\rm{rad/m^2}$ at the GRB redshift. The magnitude of the rotation measure is consistent with propagation through a dense, magnetized environment, such as a progenitor HII region. These findings demonstrate that GRB afterglows exhibit measurable linear polarization at centimeter wavelengths, and that their polarimetric properties probe both intrinsic jet magnetization and the surrounding medium. Future multi-frequency polarimetric monitoring over timescales of days to weeks will enable detailed studies of the evolution of magnetic field structure and provide new constraints on the role of magnetic fields in GRB afterglows.
fields
astro-ph.HE 4years
2026 4representative citing papers
Multi-wavelength data on GRB 260310A support an off-axis jet model explaining weak prompt emission and bright delayed afterglow, including reverse-shock signatures and late X-ray rebrightening.
GRB 260310A/SN 2026fgk is a spectroscopically confirmed Type Ic-BL supernova at z=0.153 with 0.4-0.6 times the luminosity of SN 1998bw, nickel mass 0.4-0.5 solar masses, ejected mass 4-6 solar masses, kinetic energy (3-8) x 10^51 erg, and located at a 15 kpc offset due to the host's extended light p
Overview of SKAO's role in radio follow-up of GW events, GRB afterglows, and kilonovae for system characterization and population studies.
citing papers explorer
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Constraining inhomogeneities and asymmetries in SNe, FBOTs, and other high-energy transients from unresolved radio observations
A new method infers inhomogeneities and asymmetries in high-energy transients from their radio synchrotron self-absorption spectra and demonstrates it on SN 2016coi and AT2018cow.
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An extremely bright slow-rising afterglow from an off-axis jet in GRB 260310A
Multi-wavelength data on GRB 260310A support an off-axis jet model explaining weak prompt emission and bright delayed afterglow, including reverse-shock signatures and late X-ray rebrightening.
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GRB 260310A/SN 2026fgk: Photometric and Spectroscopic Evolution of a Nearby GRB-Supernova and an Exceptionally Bright Afterglow at z=0.153
GRB 260310A/SN 2026fgk is a spectroscopically confirmed Type Ic-BL supernova at z=0.153 with 0.4-0.6 times the luminosity of SN 1998bw, nickel mass 0.4-0.5 solar masses, ejected mass 4-6 solar masses, kinetic energy (3-8) x 10^51 erg, and located at a 15 kpc offset due to the host's extended light p
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Gamma-ray Bursts and Kilonovae from Gravitational Wave Events
Overview of SKAO's role in radio follow-up of GW events, GRB afterglows, and kilonovae for system characterization and population studies.