Neutrino Emission Characteristics of Black Hole Formation in Three-Dimensional Simulations of Stellar Collapse

Neutrinos are unique probes of core-collapse supernova dynamics, especiallyin the case of black hole (BH) forming stellar collapses, where theelectromagnetic emission may be faint or absent. By investigating two 3Dhydrodynamical simulations of BH-forming stellar collapses of mass 40 and 75M_sun, we identify the physical processes preceding BH formation throughneutrinos, and forecast the neutrino signal expected in the existing IceCubeand Super-Kamiokande detectors, as well as in the future generation DUNEfacility. Prior to the abrupt termination of the neutrino signal correspondingto BH formation, both models develop episodes of strong and long-lastingactivity by the spiral standing accretion shock instability (SASI). We findthat the spiral SASI peak in the Fourier power spectrum of the neutrino eventrate will be distinguishable at 3 sigma above the detector noise for distancesup to O(30) kpc in the most optimistic scenario, with IceCube having thehighest sensitivity. Interestingly, given the long duration of the spiral SASIepisodes, the spectrograms of the expected neutrino event rate carry clearsigns of the evolution of the blue spiral SASI frequency as a function of time,as the shock radius and post-shock fluid velocity evolve. Due to the highaccretion luminosity and its large-amplitude SASI-induced modulations, anycontribution from asymmetric (dipolar or quadrupolar) neutrino emissionassociated with the lepton emission self-sustained asymmetry (LESA) is farsubdominant in the neutrino signal.