Matthew Meixner

Sterile neutrino oscillations in core-collapse supernovae

We have made core-collapse supernova simulations that allow oscillations between electron neutrinos (or their anti particles) with right-handed sterile neutrinos. We have considered a range of mixing angles and sterile neutrino masses including those consistent with sterile neutrinos as a dark matter candidate. We examine whether such oscillations can impact the core bounce and shock reheating in supernovae. We identify the optimum ranges of mixing angles and masses that can dramatically enhance the supernova explosion by efficiently transporting electron anti-neutrinos from the core to behind the shock where they provide additional heating leading to much larger explosion kinetic energies. We show that this effect can cause stars to explode that otherwise would have collapsed. We find that an interesting periodicity in the neutrino luminosity develops due to a cycle of depletion of the neutrino density by conversion to sterile neutrinos that shuts off the conversion, followed by a replenished neutrino density as neutrinos transport through the core.

Impact of sterile neutrino dark matter on core-collapse supernovae

We summarize the impact of sterile neutrino dark matter on core-collapse supernova explosions. We explore various oscillations between electron neutrinos or mixed

QCD Matter in White Dwarfs and Supernova Collapse

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The NDL Equation of State for Supernova Simulations

neutrinos and right-handed sterile neutrinos that may occur within a core-collapse supernova. In particular, we consider sterile neutrino masses and mixing angles that are consistent with sterile neutrino dark matter candidates as indicated by recent X-ray flux measurements. We find that the interpretation of the observed 3.5 keV X-ray excess as due to a decaying 7 keV sterile neutrino that comprises 100\% of the dark matter would have almost no observable effect on supernova explosions. However, in the more realistic case in which the decaying sterile neutrino comprises only a small fraction of the total dark matter density due to the presence of other sterile neutrino flavors, WIMPs, etc., a larger mixing angle is allowed. In this case a 7 keV sterile neutrino could have a significant impact on core-collapse supernovae. We also consider mixing between

A review of the impact of sterile neutrino dark matter on core-collapse supernovae

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Sterile neutrino oscillations in core-collapse supernova simulations

neutrinos and sterile neutrinos. We find, however, that this mixing does not significantly alter the explosion and has no observable effect on the neutrino luminosities at early times.

Generalized density functional equation of state for astrophysical simulations with 3-body forces and quark gluon plasma

The search for astrophysical evidence for a transition to QCD matter is an important goal. Although much effort has gone into searching for neutron star candidates, here we describe the exploration of two other possible signatures. One is the search for strange dwarfs. Masses and radii for a large number of white dwarfs have been deduced from a combination of proper motion studies, Hipparcos parallax distances, effective temperatures, and binary or spectroscopic masses. Some stars appear to have radii which are significantly smaller than that expected for a standard electron-degenerate white-dwarf equation of state. We argue that there is marginal evidence for bimodality in the radius distribution. We show that the data exhibit several features consistent with the expected mass-radius relation of strange dwarfs. We identify eight nearby white dwarfs that are possible candidates for strange matter cores and suggest observational tests of this hypothesis. We also review the current status of core-collapse supernova research, and in particular, the effects on the explosion of a QCD phase transition in the proto-neutron-star core. We describe how a first order transition could enhance the explosion and lead to observable effects in the emergent neutrino light curve.