First Evidence for a High-Energy Astrophysical Neutrino Source with IceCube
After their discovery in 1912, the origin of high-energy cosmic rays has remained one of the largest open mysteries in physics and astronomy. Detected at energies exceeding 1020 electron volts -- 10 million times the energies reached by the Large Hadron Collider -- these particles must be produced in the most violent processes in the universe. But which ones? And where? The cosmic rays themselves are electrically charged and follow curved paths in intergalactic magnetic fields, erasing evidence of their origin. Neutrinos, which are electrically neutral and are born with the cosmic rays, offer a solution to this century-old puzzle. On September 22, 2017, the IceCube Neutrino Observatory, located in a cubic kilometer of the south polar ice sheet, observed a high-energy neutrino from the direction of the distant active galaxy TXS 0506+056, providing evidence for what would be both the first known high-energy neutrino source and the first known cosmic ray source, ushering in the era of neutrino astronomy. This talk will describe how this detection was made, what it implies for our understanding of the extreme universe, and the path forward for neutrino astronomy.
Nathan Whitehorn is an assistant professor in the Department of Physics and Astronomy at UCLA, with research interests in experimental particle astrophysics and cosmology. He is a graduate of the University of Chicago and University of Wisconsin - Madison, from which he received his PhD for work on the IceCube Neutrino Observatory involving the diffuse extragalactic neutrino background and gamma-ray bursts. He was then at UC Berkeley, working on the South Pole Telescope, an instrument to observe the cosmic microwave background, before moving to the southland and joining UCLA in 2017.
"What's Up?" in this month will be presented by Chris Butler from OCA