Black Hole Accretion Disk Diffuse Neutrino Background
  We study the cosmic MeV neutrino background from accretion disks formed
during collapsars and the coalescence of compact-object mergers. We provide
updated estimates, including detection rates, of relic neutrinos from
collapsars, as well as estimates for neutrinos that are produced in mergers.
Our results show that diffuse neutrinos detected at HyperK would likely include
some that were emitted from binary neutron-star mergers. The collapsar rate is
uncertain, but at its upper limit relic neutrinos from these sources would
provide a significant contribution to the Cosmic Diffuse Neutrino Background.
