Pre-supernova neutrino emission from massive stars and their detection

Recent progress of neutrino detectors makes it possible to detect pre-SN neutrinos, which are emitted from the core of massive stars before supernova explosions. Pre-SN neutrino observations will become an alarm for supernovae. We hence calculate the number luminosity and energy spectra of pre-SN neutrinos from the 15 M _o progenitor based on the state-of-the-art calculations of massive stars. We find that the number luminosity of v_e 's is before core collapse and core bounce, respectively, whereas that of. We then estimate the number of neutrino events at neutrino detectors taking neutrino oscillations into the obtained luminosities and spectra. We find that an alarm is issued a few days before the explosion by detecting 's at liquid-scintilation type detectors if the progenitor is located at 200 pc. Finally, we perform a systematic study of pre-SN neutrino emission for 7 progenitor models with different initial masses. We find that the difference of the number luminosities is ∼ 1 order and the dependence of the initial mass have to be taken into the theoretical predictions of pre-SN neutrino observations.