Astrophysical high energy neutrinos

Astrophysical candidate sources of ultrahigh-energy cosmic-rays are also expected to produce high-energy neutrinos in situ and around their acceleration sites by interacting with abundant soft photons or nucleons. Detection of these neutrinos then may identify the yet unknown sources of the cosmic rays. I discuss different models of high-energy neutrino signals from astrophysical objects such as gamma-ray bursts and hyper-novae, and how detection/non-detection of these astronomical messengers may constrain the source models. I also discuss the detectability of these neutrinos in upcoming neutrino telescopes and how flavor tagging may be used to learn about the astrophysics of the sources.