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“Ghost particles” have been detected at the center of a galaxy for te first time ever

Por: Ecoo sfera8 de noviembre de 2022

For the first time ever, a ghost particle from the center of a nearby active galaxy has been detected.

Neutrinos are the most elusive particles in the entire Universe and perhaps also the most mysterious, as one of their flavors is an ideal candidate to explain dark matter. Physicists do not yet understand much about their erratic behavior, although new research using data from IceCube, the largest neutrino detector deep in Antarctica, may shed light on these mysterious particles.

Neutrinos: the ghost particles

We know that the Universe is a complex soup where different particles and antiparticles of all varieties, such as protons, electrons, positrons, and others more unstable than all of the above, the neutrinos, intermingle and interact.

Neutrinos are one of the fundamental particles in the composition of the Universe. They are neutral, i.e., they have no charge, and they are also incredibly tiny, so they generate an extremely interesting phenomenon. Because they have such a small interaction cross section with matter, they can travel through the Universe practically unstoppably. This is why they have been called ‘ghost’ particles.

So far, physicists know that neutrinos are extremely high-energy particles that are released from different nuclear processes such as fission and fusion, as well as a wide variety of decay processes. This means that we are just now being invaded by a shower of neutrinos from the Sun and other cosmic radioactive processes such as supernovae.

But in addition to being incredibly tiny, neutrinos are highly unstable, meaning that any interaction during their journey through the cosmos, which for now is unclear, generates a change of ‘flavor’ (as particle physicists call it). To date, three flavors of neutrinos are known: electron, muon, and tau.

Detecting neutrinos that exceed the energy of the Sun

The largest neutrino detector in human possession is located in Antarctica and is composed of 86 string detectors that descend into a cubic kilometer of ice. Called IceCube, the detector became operational more than a decade ago, in May 2011.

Whenever the Earth is invaded by neutrino showers from any source, they strike the glacial ice, producing particles of all varieties, provided there is enough energy to create them. The resulting particles then interact with the ice and emit a cone-shaped mixture of blue and ultraviolet light known as Cherenkov radiation. This visible radioactive fingerprint tells scientists where and how the particles were created. In other words, it allows neutrinos to be studied without even having to observe them, simply by reconstructing the Cherenkov signals.

Several neutrinos have been detected before, but never from a nearby active galaxy until a new investigation detected 79 high-energy events (more than one trillion electron volts) from Messier 77. The galaxy in question, also called NGC 1068, is only 47 million light-years away and is the first to be detected through its neutrino signature.

The energy emanated by the Massier 77 neutrinos exceeds all measurements since it is more than one trillion electron volts, which is equivalent to 750 million times the energy emitted by the Sun. And the most surprising thing is that this energy comes from a galaxy whose central supermassive black hole weighs only 15 million times the mass of the Sun.

Story originally published in Spanish in Ecoosfera

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