First radio polarization measurement of a gamma-ray burst afterglow
A group of astronomers has recorded polarized radio emission from the afterglow of a gamma-ray burst (GRB) for the first time, using the U.S. National Science Foundation Very Large Array (NSF VLA). The observatory is managed by the National Radio Astronomy Observatory (NRAO) on behalf of the foundation.
Gamma-ray bursts rank among the most violent phenomena in the cosmos. They are brief but immensely energetic flashes produced when very massive stars collapse or compact objects merge. The afterglow they leave behind carries information about the physical environment of the explosion.
Significance of the polarization
The observed polarization of the radio signal serves as a magnetic fingerprint of the cosmic catastrophe. It provides clues to the geometry and orientation of the magnetic fields involved in the event. Prior to this work, such detections had not been achieved at radio frequencies.
- Instrument: NSF Very Large Array
- Band: radio wavelengths
- Target: gamma-ray burst afterglow
- Result: first polarization detection
The team describes the finding as a landmark in the study of gamma-ray bursts. Further observations may improve understanding of magnetic field behavior in these events and help test models of how GRBs form.