Authors: Evan O'Connor, Christian D. Ott
Date: 27 Oct 2010
Abstract: We present results of a systematic study of failing core-collapse supernovae and the formation of stellar-mass black holes (BHs). Using our open-source general-relativistic 1.5D code GR1D equipped with a 3-flavor neutrino leakage/heating scheme and over 60 presupernova models, we study the effects of the choice of nuclear equation of state, zero-age main sequence (ZAMS) mass and metallicity, rotation, and mass loss prescription on BH formation. We find that the outcome of collapse, for a given equation of state, can be predicted, to first order, by a single parameter, the compactness of the stellar core at bounce. By comparing protoneutron star (PNS) structure at the onset of gravitational instability with solutions of the TOV equations, we find that thermal pressure support in the outer PNS core is responsible for raising the maximum PNS mass by up to 25% above the cold NS value. By artificially increasing neutrino heating, we find the critical neutrino heating efficiency required for exploding a given progenitor structure and connect these findings with ZAMS conditions, establishing, albeit approximately, for the first time based on actual collapse simulations, the mapping between ZAMS parameters and the outcome of core collapse. We also study the effect of progenitor rotation and find that the dimensionless spin of nascent black holes may be robustly limited below a* = Jc/GMˆ2 = 1 by the appearance of nonaxisymmetric rotational instabilities.
© M. Vallisneri 2012 — last modified on 2010/01/29
Tantum in modicis, quantum in maximis