Elusive neutrinos caught streaming out of a black hole hidden in dust
A unique observatory buried in pristine Antarctic ice discovered a stream of elusive neutrino particles streaming from the center of a distant galaxy obscured by dust.
The observation by the IceCube Observatory at the South Pole is only the second detection of a cosmic source neutrinosand scientists hope it can shed light on what’s happening inside the supermassive black holes.
Neutrinos are strange. They are everywhere, but most of the time they don’t interact with other particles or other types of matter. That’s because they have very little mass and no electrical charge. For this reason, they are incredibly difficult to spot. But their total indifference to their environment also means that, unlike other particles, they are not distracted from their path and travel long distances in straight lines from their sources. That means that once astronomers know how to detect them, they can track neutrinos to their origin much more easily than other types of particles.
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An international team of scientists has now reported detecting such a stream of neutrinos from a universe known as NGC 1086 (which is sometimes called Messier 77 or the Squid Galaxy). NGC 1086 is a dusty galaxy, with a shape very similar to that of the Milky Way. However, NGC 1086 produces eruptions of stars at a much faster speed than our galactic home and is whirling around a black hole much more massive than the one at the center of the Milky Way.
Devouring massive amounts of material, this hungry black hole forms a nucleus of a sparkling active galactic core that releases bright bursts of high-energy cosmic rays and charged particles that outshine the galaxy’s stars. However, most of the black hole’s crackles are hidden from view because the center of the galaxy is obscured by a thick ring, seen from Soil. However, the neutrinos, with their ability to pass through matter, escape this ring and reach our planet undisturbed.
“We are peering into active regions of the NGC 1068 galaxy 47 million light-years away,” said Gary Hill, an associate professor of physics at the University of Adelaide in Australia and one of the authors of the paper, in a statement. pronunciation (opens in new tab). “Observing neutrinos emitted by this, we will be able to learn more about the extreme particle acceleration and production processes that take place in the galaxy, which has not been possible until now because other high-energy emissions cannot escape from it.”
The detection makes NGC 1068 only the second source of cosmic neutrinos ever identified. In 2018, the IceCube Observatory found a stream of neutrinos emanating from an active galactic core of a galaxy known as TXS 0506+056.
Located in the constellation Orion, that galaxy is 100 times farther from Earth than NGC 1068, but emits a beam of material nearly the speed of light, pointing directly at Earth. That makes radiation from TXS 0506+056 much easier to recognize than that from NGC 1068.
“After the 2018 excitement of the discovery of neutrinos from TXS 0506+056, it’s even more exciting to find a source that produces a steady stream of neutrinos that we can see with IceCube,” Hill said. “The fact that neutrinos can escape from these otherwise obscured regions of the universe means that they are also difficult to detect.”
The IceCube observatory is a unique installation. It consists of more than 5,000 detectors submerged at a depth of 0.9 to 1.5 miles (1.5 to 2.5 kilometers) in the pristine Antarctic ice. Suspended from 86 vertical cables spaced 125 meters apart, the detectors record tiny flashes of blue light that are activated when high-energy neutrinos collide with the atomic nuclei of the ice molecules.
Built in the 2000s, the observatory has been operational since 2010. The recent study analyzed detections of high-energy neutrinos made between 2011 and 2020, looking for possible sources of those particles at known active galaxies. Computer modeling previously suggested that active black holes, such as those at the center of NGC 1068, must be able to accelerate particles and throw them into intergalactic space along with bursts of high-energy radiation. Scientists expect other similar galaxies to produce their own neutrino currents.
“One neutrino can pick a source. But only a multiple neutrino observation will reveal the obscured core of the most energetic cosmic objects,” said Francis Halzen, a professor of physics at the University of Wisconsin-Madison and principal investigator of the IceCube project. in a separate pronunciation (opens in new tab). “IceCube has collected about 80 neutrinos of tera electron volt energy from NGC 1068, which is not yet enough to answer all our questions, but they are certainly the next big step towards the realization of neutrino astronomy. “
Astronomers are currently planning a second-generation IceCube detector that can detect a thousand times more neutrinos and detect five times weaker sources. Gradually, the astronomers said, the eclipsed… universe will open, leading to a new era in astronomy.
NGC 1068 could become a “standard candle” for this future neutrino research, Theo Glauch, a postdoctoral associate at the Technical University of Munich (TUM) in Germany and co-author of the paper, said in the statement. Discovered in 1780, the galaxy is well known to astronomers and has been studied for centuries.
The study (opens in new tab) was published Nov. 4 in the journal Science.
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