The Observation of High-Energy Neutrinos from the Cosmos: Lessons Learned for Multimessenger Astronomy

Abstract

The IceCube neutrino telescope discovered PeV-energy neutrinos originating beyond our Galaxy with an energy flux that is comparable to that of GeV-energy gamma rays and EeV-energy cosmic rays. These neutrinos provide the only unobstructed view of the cosmic accelerators that power the highest energy radiation reaching us from the universe. We will review the results from IceCube's first decade of operations, emphasizing the measurement of the diffuse multiflavored neutrino flux from the universe and the identification of the supermassive black hole TXS 0506+056 as a source of cosmic neutrinos and, therefore, cosmic rays. We will speculate on the lessons learned for multimessenger astronomy, among them that extragalactic neutrino sources may be a relatively small subset of the cosmic accelerators observed in high-energy gamma rays and that these may be gamma-ray-obscured at the times that they emit neutrinos.

Advancing the Landscape of Multimessenger Science in the Next Decade

“…Similarly, the neutrinos from SN 1987A by themselves confirmed the basic paradigm of core-collapse supernovae and the time difference between the arrival of the neutrinos and electromagnetic radiation allows us to place upper limits on the neutrinos mass [24]. Finally, the detection of neutrinos from the blazar TXS 0506+056 in coincidence with a flair seen in gamma rays provides information about the baryon content of the relativistic material in the jet-which photons by themselves cannot constrain-upending the long-held belief that electrons were the dominant source of the gamma rays [25].…”

Astrophysical Neutrinos and Blazars

“…The IHBL 1ES1959+650, the next object in order of significance in the list of probable flaring sources of ref. [38], was also noticed as a possible counterpart of three neutrinos detected by AMANDA, the predecessor of IceCube, in 2002 in correspondence of a rare high-energy γ-ray flare [70].…”