Cosmic Closure: Relating the Ultimate Fate of Massive Stars and the Ultimate Fate of the Universe

We give a brief overview of the status of core collapse supernova modeling, particularly as it pertains to predictions of neutrino signatures for the next galactic or near extragalactic supernova. We also consider the implications of neutrino mass for both the supernova mechanism and neutrino signature predictions

Core-Collapse Supernovae at the Threshold

Recent progress in modeling core-collapse supernovae is summarized and set in perspective. Two-dimensional simulations with state-of-the-art treatment of neutrino transport still fail to produce powerful explosions, but evidence is presented that they are very close to success.Comment: 8 pages, 3 figures, high-quality available upon request; contribution to Procs. IAU Coll. 192, "Supernovae", Eds. J.M. Marcaide ad K.W. Weiler, Springe

On the temperature dependence of the symmetry energy

We perform large-scale shell model Monte Carlo (SMMC) calculations for many nuclei in the mass range A=56-65 in the complete pfg_{9/2}d_{5/2} model space using an effective quadrupole-quadrupole+pairing residual interaction. Our calculations are performed at finite temperatures between T=0.33-2 MeV. Our main focus is the temperature dependence of the symmetry energy which we determine from the energy differences between various isobaric pairs with the same pairing structure and at different temperatures. Our SMMC studies are consistent with an increase of the symmetry energy with temperature. We also investigate possible consequences for core-collapse supernovae events

Differential Neutrino Rates and Emissivities from the Plasma Process in Astrophysical Systems

The differential rates and emissivities of neutrino pairs from an equilibrium plasma are calculated for the wide range of density and temperature encountered in astrophysical systems. New analytical expressions are derived for the differential emissivities which yield total emissivities in full agreement with those previously calculated. The photon and plasmon pair production and absorption kernels in the source term of the Boltzmann equation for neutrino transport are provided. The appropriate Legendre coefficients of these kernels, in forms suitable for multi-group flux-limited diffusion schemes are also computed.Comment: 27 pages and 10 figures. Submitted to Phys. Rev.

The photo-neutrino process in astrophysical systems

Explicit expressions for the differential and total rates and emissivities of neutrino pairs from the photo-neutrino process $e^\pm + \gamma \to e^\pm + \nu + \bar\nu$ in hot and dense matter are derived. Full information about the emitted neutrinos is retained by evaluating the squared matrix elements for this process which was hitherto bypassed through the use of Lenard's identity in obtaining the total neutrino emissivities. Accurate numerical results are presented for widely varying conditions of temperature and density. Analytical results helpful in understanding the qualitative behaviors of the rates and emissivities in limiting situations are derived. The corresponding production and absorption kernels in the source term of the Boltzmann equation for neutrino transport are developed. The appropriate Legendre coefficients of these kernels, in forms suitable for multigroup flux-limited diffusion schemes are also provided.Comment: 26 pages and 7 figures. Version as accepted in Phys. Rev. D; three figures and related discussion revise

Supernova Bounds on Majoron-emitting decays of light neutrinos

Neutrino masses arising from the spontaneous violation of ungauged lepton-number are accompanied by a physical Goldstone boson, generically called Majoron. In the high-density supernova medium the effects of Majoron-emitting neutrino decays are important even if they are suppressed in vacuo by small neutrino masses and/or small off-diagonal couplings. We reconsider the influence of these decays on the neutrino signal of supernovae in the light of recent Super-Kamiokande data on solar and atmospheric neutrinos. We find that majoron-neutrino coupling constants in the range 3\times 10^{-7}\lsim g\lsim 2\times 10^{-5} or g \gsim 3 \times 10^{-4} are excluded by the observation of SN1987A. Then we discuss the potential of Superkamiokande and the Sudbury Neutrino Observatory to detect majoron neutrino interactions in the case of a future galactic supernova. We find that these experiments could probe majoron neutrino interactions with improved sensitivity.Comment: 28 pages, 5 figure

Slowly Rotating General Relativistic Superfluid Neutron Stars with Relativistic Entrainment

Neutron stars that are cold enough should have two or more superfluids/supercondutors in their inner crusts and cores. The implication of superfluidity/superconductivity for equilibrium and dynamical neutron star states is that each individual particle species that forms a condensate must have its own, independent number density current and equation of motion that determines that current. An important consequence of the quasiparticle nature of each condensate is the so-called entrainment effect, i.e. the momentum of a condensate is a linear combination of its own current and those of the other condensates. We present here the first fully relativistic modelling of slowly rotating superfluid neutron stars with entrainment that is accurate to the second-order in the rotation rates. The stars consist of superfluid neutrons, superconducting protons, and a highly degenerate, relativistic gas of electrons. We use a relativistic $\sigma$ - $\omega$ mean field model for the equation of state of the matter and the entrainment. We determine the effect of a relative rotation between the neutrons and protons on a star's total mass, shape, and Kepler, mass-shedding limit.Comment: 30 pages, 10 figures, uses ReVTeX

Presupernova Structure of Massive Stars

Issues concerning the structure and evolution of core collapse progenitor stars are discussed with an emphasis on interior evolution. We describe a program designed to investigate the transport and mixing processes associated with stellar turbulence, arguably the greatest source of uncertainty in progenitor structure, besides mass loss, at the time of core collapse. An effort to use precision observations of stellar parameters to constrain theoretical modeling is also described.Comment: Proceedings for invited talk at High Energy Density Laboratory Astrophysics conference, Caltech, March 2010. Special issue of Astrophysics and Space Science, submitted for peer review: 7 pages, 3 figure

Relativistic Wigner Function Approach to Neutrino Propagation in Matter

In this work we study the propagation of massive Dirac neutrinos in matter with flavor mixing, using statistical techniques based on Relativistic Wigner Functions. First, we consider neutrinos in equilibrium within the Hartree approximation, and obtain the corresponding relativistic dispersion relations and effective masses. After this, we analyze the same system out of equilibrium. We verify that, under the appropiate physical conditions, the well known equations for the MSW effect are recovered. The techniques we used here appear as an alternative to describe neutrino properties and transport equations in a consistent way.Comment: 18 pages, no figures. Revte