Extreme Black Hole in Squid Galaxy Produces High-Energy Neutrinos

The IceCube Neutrino Observatory has detected a strong signal of energetic neutrinos coming from NGC 1068, known as the Squid Galaxy. This barred spiral galaxy is located about 47 million light-years away in the constellation Cetus. Usually, galaxies that emit high-energy neutrinos also show strong gamma-ray signals. However, the Squid Galaxy presents a puzzling case because its gamma-ray emissions are very weak despite the strong neutrino detection.

Neutrinos are tiny particles that rarely interact with matter, allowing them to travel great distances through space without being blocked. IceCube, a detector at the South Pole, captures these rare neutrinos as they pass through the Earth. The Squid Galaxy’s core hosts a supermassive black hole that feeds on gas and dust. In many active galaxies, collisions between protons and photons near the black hole create both neutrinos and gamma-rays, but the Squid Galaxy’s gamma-ray output is much lower than expected.

Scientists suggest that the energetic neutrinos detected from NGC 1068 come from a different process. The jets emitted by the supermassive black hole produce intense ultraviolet radiation that breaks apart helium nuclei. When these helium nuclei collide with ultraviolet photons near the galaxy’s center, they release neutrons. These neutrons then decay and produce neutrinos with energy levels matching the IceCube observations.

This explanation helps solve the mystery of why the Squid Galaxy has strong neutrino signals but weak gamma-ray emissions. The research was published recently in the journal Physical Review Letters. The study offers new insight into the behavior of supermassive black holes and their surrounding environments.

Understanding neutrinos from galaxies like NGC 1068 allows scientists to learn more about extreme cosmic events. It also sheds light on the origins of high-energy particles in the universe. The Squid Galaxy’s unusual neutrino activity shows how much remains to be discovered about the universe’s most powerful forces.