Astronomers Capture First Polarized Gamma-Burst Radius Signals – Xinhua


An international team of astronomers has captured the first polarized radio waves from a distant cosmic explosion known as the GRB 190114C gamma ray explosion.

Astronomers have hypothesized that cosmic magnetic fields can flow through the jets, helping them form and provide structural support.

To obtain measurements of these magnetic fields, the international team employed a new trick. They observed the jets in linearly polarized light, which is sensitive to the size of the magnetic field fragments. Larger magnetic field patches, for example, produce more polarized light.

On January 14, 2019, a gamma-ray flash triggered NASA's Swift satellite, which warned astronomers of the location of the explosion in the direction of the constellation Fornax. Astronomers used the Atacama Large Millimeter / Submillimeter Array (ALMA) telescope in Chile to search for radio waves from the explosion, which occurred more than 4.5 billion years ago in a galaxy 7 billion light-years away.

The team detected a subtle, yet revealing, polarization signal of 0.8 percent, implying in magnetic field areas the size of our solar system.

Then the researchers will combine this new information with X-ray data and visible light telescopes.

"The low frequency data from the Very Large Array (VLA) in New Mexico helped confirm that we were seeing the light from the jet itself and not from the interaction of the jet with its environment," said Kate Alexander of the NASA Einstein Fellow. the observations of the VLA.

"Magnetic fields are omnipresent but notoriously difficult to restrict in our universe," said Wen-fai Fong, assistant professor of astrophysics at the Weinberg College of Arts and Sciences. "The fact that we have been able to detect its presence, not to mention the fastest jets we know, is an incredible and celebrated feat of observation."

Gamma-ray bursts produce powerful jets that travel close to the speed of light and glow with the incredible brilliance of over one billion combined suns. As these jets are extremely bright at radio wavelengths, the discovery of polarized radio signals may offer new clues to help solve this mystery. Polarization is a property of light that indicates how a magnetic field is organized and structured in a jet.

The research, published on the UN website on Wednesday, was published last week in The Astrophysical Journal Letters.


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