Organized by: Prof. Lu Lu

Events on Tuesday, July 26th, 2016

Neutrino Signal of Collapse-Induced Thermonuclear Supernovae: The Case for Prompt Black Hole Formation in SN1987A

Time: 2:00 pm - 3:00 pm

Place: 4274 Chamberlin Hall

Speaker: Kfir Blum, Weizmann Institute

Abstract: Collapse-induced thermonuclear explosion (CITE) may explain core-collapse supernovae (CCSNe). We analyze the neutrino signal in CITE and compare it to the neutrino burst of SN1987A. For strong CCSNe, as SN1987A, CITE predicts a proto-neutron star (PNS) accretion phase lasting up to a few seconds that is cut-off by black hole (BH) formation. The neutrino luminosity can later be revived by accretion disc emission after a dead time of few to few ten seconds. In contrast, the neutrino mechanism for CCSNe predicts a short (< 1sec) PNS accretion phase followed by slowly declining PNS cooling luminosity. We repeat statistical analyses used in the literature to interpret the neutrino mechanism, and apply them to CITE. The first 1-2 sec of the neutrino burst are equally compatible with CITE and with the neutrino mechanism. However, the data hints towards a luminosity drop at t~2-3 sec, in some tension with the neutrino mechanism but naturally attributed to BH formation in CITE. The occurrence of neutrino signal events at 5 sec suggests that, within CITE, accretion disc formed by that time. We perform 2D numerical simulations, showing that CITE may be able to accommodate this disc formation time while reproducing the ejected Ni56 mass and ejecta kinetic energy within factors 2-3 of observations. We estimate the accretion disc neutrino luminosity, finding it on the low side but compatible with data to a factor of 10. Given current uncertainties in disc simulations we conclude that direct BH formation may have occurred in SN1987A.<br>

Host: Markus Ahlers

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