Speaker
Description
Multmessenger follow-up observations triggered by high-energy neutrino signals offer a robust method for identifying cosmic ray (CR) sources, particularly when the sources are transient. In this talk, we propose a viable strategy for multimessenger observations to understand the origin of CRs. Optical transients, such as core-collapse supernovae, are among the major candidates for CR and neutrino sources, especially in the 10-100 TeV range. We show that demanding multiplet neutrino detection by a large neutrino telescope limits the distances of detectable neutrino sources, which allows us to identify emissions from abundant classes of objects by eliminating the possibility of the chance coincident transient detections. In the neutrino energy range above 100 TeV, the most likely source candidates are X-ray transients, particularly if the cosmic neutrino background radiation above 100 TeV originates from the same class of objects that emit ultrahigh-energy CRs (UHECRs). We demonstrate that this hypothesis is supported by model-indepent arguments. We illustrate how searches for X-ray counterparts conducted by wide-field X-ray satellites, such as Einstein Probe, provide insights into the unification models for UHECRs and neutrinos. The resulting bounds on the source parameter space place stringent constraints on the properties of UHECR origins.
