NASA's X-ray photos of the area surrounding the supermassive black hole of Milky Way Galaxy.
The giant black hole at the centre of the Milky Way may be producing the mysterious high-energy neutrinos, NASA scientists have found.
If confirmed, this would be the first time that scientists have traced neutrinos back to a black hole. Neutrinos are tiny particles that carry no charge and interact very weakly with electrons and protons.
Unlike light or charged particles, neutrinos can emerge from deep within their cosmic sources and travel across the universe without being absorbed by intervening matter or, in the case of charged particles, deflected by magnetic fields.
The Earth is constantly bombarded with neutrinos from the sun. However, neutrinos from beyond the solar system can be millions or billions of times more energetic.
Scientists have long been searching for the origin of ultra-high energy and very high-energy neutrinos.
"We now have the first evidence that an astronomical source, the Milky Way's supermassive black hole may be producing these very energetic neutrinos," said Yang Bai of the University of Wisconsin in Madison.
Because neutrinos pass through material very easily, it is extremely difficult to build detectors that show exactly where the neutrino came from.
The IceCube Neutrino Observatory, located under the South Pole, has detected 36 high-energy neutrinos since the facility became operational in 2010.
By pairing IceCube's capabilities with the data from the three X-ray telescopes, scientists were able to look for violent events in space that corresponded with the arrival of a high-energy neutrino on Earth.
"We checked to see what happened after Chandra X-ray Observatory witnessed the biggest outburst ever detected from Sagittarius A, the Milky Way's supermassive black hole," said co-author Andrea Peterson, also of the University of Wisconsin.
"And less than three hours later, there was a neutrino detection at IceCube," said Peterson.
In addition, several neutrino detections appeared within a few days of flares from the supermassive black hole.
"It would be a very big deal if we find out that Sagittarius A produces neutrinos," said co-author Amy Barger of the University of Wisconsin.
The study was published in the journal Physical Review D.