Astronomers detect magnetic fingerprint of gamma-ray burst for first time
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Astronomers using the NSF Very Large Array radio telescope detected polarized light from a gamma-ray burst afterglow at radio wavelengths for the first time. The observation provides direct evidence of magnetic fields in the explosion's jet. The finding challenges existing models of GRB emission mechanisms.
The Observation
The team, led by researchers from the University of Bath, observed GRB 221009A, one of the brightest gamma-ray bursts ever recorded. Using the NSF VLA, they detected polarized radio emission from the afterglow, indicating ordered magnetic fields in the jet. The polarization fraction reached up to 70% in some bands.
Scientific Significance
This is the first time polarized light has been measured from a GRB afterglow at radio wavelengths. The detection confirms that magnetic fields play a key role in shaping the jet and accelerating particles. Previous models assumed magnetic fields were chaotic or weak.
What's Next
The team plans to observe more GRBs with the VLA and the upcoming Next Generation VLA. It remains unclear whether all GRBs produce similarly ordered magnetic fields or if GRB 221009A is exceptional.
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Astronomers detect magnetic fingerprint of gamma-ray burst for first time
