The IceCube Neutrino Observatory – a network of thousands of sensors located deep in the ice below the South Pole – has identified neutrino emission from NGC 1068, a nearby active galaxy also known as Messier 77. According to the study, the newly identified source’s properties are quite different from the high-energy blazar TXS 0506+56, which was previously identified as a neutrino source. The authors suggest that there is likely to be more than one population of sources contributing to the observed cosmic neutrino background. Observations have indicated that there is a diffuse background of neutrinos from extragalactic sources. These high-energy neutrinos are thought to be produced by cosmic rays when they collide with matter or radiation inside sufficiently energetic astrophysical objects, such as active galaxies containing supermassive black holes . However, identifying the individual sources that produce neutrinos remains challenging. Here, the IceCube Collaboration – an international group of more than 400 researchers – analyzed data collected with the IceCube Neutrino Observatory between 2011 and 2020 to search for point sources of neutrino emission. They identify the nearby active galaxy NGC 1068 as a source of high-energy neutrinos. In a related Perspective, Kohta Murase writes “Radio-quiet AGNs [active galactic nuclei], including NGC 1068, and other low-luminosity AGNs, which are more abundant than blazars and radio-loud AGNs, might help explain the amount of all cosmic neutrinos observed by the IceCube Neutrino Observatory.”
Science
Evidence for neutrino emission from the nearby active galaxy NGC 1068
4-Nov-2022