(ORDO NEWS) — The role of active supermassive black holes in the production of high-energy neutrinos from outside the Milky Way seems to be confirmed.
For the second time, physicists have traced these so-called “ghost” particles to the heart of the galaxy across the gulf of intergalactic space.
With this discovery, we can start a real census of extragalactic neutrino factories. , and use the properties of neutrinos to understand their home environment.
The galaxy in question is a well-studied object known as NGC 1068, also known as Messier 77 or the Squid Galaxy – a beautiful barred spiral about 47 million light-years away, close enough to be seen with binoculars.
And scientists have counted dozens of neutrinos in the high-energy tera-electronvolt (TeV) range emanating from its direction.
Previously, the only high-energy neutrino was a single TeV particle tracked to an extragalactic source that was traced to a type of galaxy called a blazar named TXS 0506+056, about 3.8 billion light-years away.
This makes a new set of data obtained over 10-year period of the IceCube neutrino observatory, the absolute Treasury.
“One neutrino can single out a source. But only observations with multiple neutrinos will reveal the hidden core of the most energetic space objects,” says physicist Francis Halzen of the University of Wisconsin-Madison and IceCube principal investigator.
“IceCube has accumulated about 80 neutrinos. teraelectronvolt energy neutrinos from NGC 1068, which are not yet enough to answer all our questions, but they are definitely the next big step towards realizing neutrino astronomy.”
Neutrinos are nearly massless subatomic particles formed by radioactive decay that pervades the universe.
They flow constantly, through everything, among the most abundant particles in the universe. They are flowing through you, right now.
And that’s what makes them tricky to detect: they hardly interact with anything.
For neutrinos, normal matter in the universe can also be smoke and shadows. That’s why we call them ghost particles.
It is however precisely this property that makes them such a potential useful study. Since they are not influenced by the Universe, they always move in a straight line.
And high-energy neutrinos are produced exclusively in processes associated with the acceleration of cosmic rays, such as powerful jets generated in space. extreme conditions around an active supermassive black hole.
However, if we want to know about these neutrino factories, we need to find neutrinos, and this is where IceCube comes in.
Dark Antarctic ice, photodetectors look for streams of light that occur when neutrinos sometimes interact with atoms or molecules.
And this is how, thanks to close international cooperation, a careful analysis of the data collected by the observatory over 10 years, it was possible to identify 80 high-energy neutrinos in the range from 1.5 to 15 TeV, tracing a straight line back to NGC 1068.
NGC 1068, as we have already noted, is an active galaxy. It’s a barred spiral like the Milky Way; unlike the Milky Way, the supermassive black hole at the center of NGC 1068 is devouring matter from its surroundings at breakneck speed.
A black hole is surrounded at the equator by a huge torus and a disk of dust and gas. It revolves around and feeds on the black hole; gravity and friction in the torus and disk produce an insane amount of heat and light.
Not all material ends up outside the event horizon of a black hole. Part of it, according to scientists, accelerates along the lines of force of the black hole’s magnetic field to the poles, from where it is thrown into space in the form of powerful plasma jets that pierce space almost at the speed of light.
If the jet is pointing in our direction, we call this galaxy a blazar; TXS 0506+056 is a blazar, and analysis shows that its 300 TeV neutrino was produced in a jet toward Earth.
Jet NGC 1068 is not directed in our direction. In fact, the galaxy is oriented in such a way that most of the high-energy light from the active galactic nucleus is hidden by dense dust. This means that neutrinos could be a way to explore a black hole that is difficult to study in other ways.
“The latest models of the black hole environment in these objects suggest that gas, dust and radiation must block the gamma rays that would otherwise accompany neutrinos,” says physicist Hans Niederhausen of Michigan State University.
“Detection of neutrinos in the core of NGC 1068 will improve our understanding of the environment around supermassive black holes.”
The team interprets neutrinos as the signature of particle acceleration and says the discovery suggests that active galactic nuclei make a significant contribution to the space-filling population of neutrinos.
They also say that this discovery is a breakthrough in neutrino astronomy and that NGC 1068 could become one of the cornerstones in this field in the future.
“A few years ago, NSF initiated an ambitious project to expand our understanding of the universe by combining established abilities in optical and radio astronomy with new capabilities for detecting and measuring phenomena such as neutrinos and gravitational waves,” says physicist Denise Caldwell of the National Science Foundation, who funded icecube.
“The IceCube neutrino observatory has identified a nearby galaxy as a cosmic source of neutrinos – this is just the beginning of this new and exciting field that promises insight into the undiscovered power of massive black holes and other fundamental properties of the universe.”
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