Neutrino Emissions in All Flavors up to the Pre-bounce of Massive Stars and the Possibility of Their Detections

This paper is a sequel to our 2015 paper, Kato et al., which calculated the luminosities and spectra of electron-type anti-neutrinos (ν[overbar]_e) from the progenitors of core-collapse supernovae. Expecting that the capability to detect electron-type neutrinos (ν_e) will increase dramatically with the emergence of liquid-argon detectors such as DUNE, we broaden the scope in this study to include all flavors of neutrinos emitted from the pre-bounce phase. We pick up three progenitor models of electron capture supernovae (ECSNe) and iron-core collapse supernovae (FeCCSNe). We find that the number luminosities reach ~10^(57) s^(–1) and ~10^(53) s^(–1) at maximum for ν_e and ν[overbar]_e, respectively. We also estimate the numbers of detection events at terrestrial neutrino detectors including DUNE, taking flavor oscillations into account and assuming the distance to the progenitors to be 200 pc. It is demonstrated that ν[overbar]_e from the ECSN progenitor will be undetected at almost all detectors, whereas we will be able to observe ≳15,900 ν_e at DUNE for the inverted mass hierarchy. From the FeCCSN progenitors, the number of ν[overbar]_e events will be largest for JUNO, 200–900 ν[overbar]_e, depending on the mass hierarchy, whereas the number of ν_e events at DUNE is ≳2100 for the inverted mass hierarchy. These results imply that the detection of ν[overbar]_e is useful to distinguish progenitors of FeCCSNe from those of ECSNe, while ν_e will provide us with detailed information on the collapse phase regardless of the type and mass of the progenitor.