Thermal neutrinos from pre-supernova

We would like to discuss prospects for neutrino observations of the core-collapse supernova progenitor during neutrino-cooled stage. We will present new theoretical results on thermal neutrino and antineutrino spectra produced deep inside the pre-supernova core. Three competing processes: pair-, photo and plasma-neutrino production, are taken into account. The results will be used to estimate signal in existing and future neutrino detectors. Chance for supernova prediction is estimated, with possible aid to core-collapse neutrino and gravitational wave detectors in the form of early warning.Comment: 1 page, Contribution to the Proceedings of Neutrino 2006 Conferenc

Toward connecting core-collapse supernova theory with observations: I. Shock revival in a 15 Msun blue supergiant progenitor with SN 1987A energetics

We study the evolution of the collapsing core of a 15 Msun blue supergiant supernova progenitor from the core bounce until 1.5 seconds later. We present a sample of hydrodynamic models parameterized to match the explosion energetics of SN 1987A. We find the spatial model dimensionality to be an important contributing factor in the explosion process. Compared to two-dimensional simulations, our three-dimensional models require lower neutrino luminosities to produce equally energetic explosions. We estimate that the convective engine in our models is 4% more efficient in three dimensions than in two dimensions. We propose that the greater efficiency of the convective engine found in three-dimensional simulations might be due to the larger surface-to-volume ratio of convective plumes, which aids in distributing energy deposited by neutrinos. We do not find evidence of the standing accretion shock instability nor turbulence being a key factor in powering the explosion in our models. Instead, the analysis of the energy transport in the post-shock region reveals characteristics of penetrative convection. The explosion energy decreases dramatically once the resolution is inadequate to capture the morphology of convection on large scales. This shows that the role of dimensionality is secondary to correctly accounting for the basic physics of the explosion. We also analyze information provided by particle tracers embedded in the flow, and find that the unbound material has relatively long residency times in two-dimensional models, while in three dimensions a significant fraction of the explosion energy is carried by particles with relatively short residency times.Comment: accepted for publication in Astrophysical Journa

Gaussian integration with rescaling of abscissas and weights

An algorithm for integration of polynomial functions with variable weight is considered. It provides extension of the Gaussian integration, with appropriate scaling of the abscissas and weights. Method is a good alternative to usually adopted interval splitting.Comment: 14 pages, 5 figure

Generalized three body problem and the instability of the core-halo objects in binary systems

Goal of the presented research is to construct simplified model of the core-halo structures in binary systems. Examples are provided by Thorne-Zytkov objects, hot Jupiters, protoplanets with large moons, red supergiants in binaries and globular clusters with central black hole. Instability criteria due to resonance between internal and orbital frequencies in such a systems has been derived. To achieve assumed goals, generalized planar circular restricted three body problem is investigated with one of the point masses, $M$, replaced with spherical body of finite size. Mechanical system under consideration includes two large masses $m$ and $M$ and the test body with small mass $\mu$. Only gravitational interactions are considered. Equations of motion are presented, and linear instability criteria are derived using quantifier elimination. Motion of the test mass $\mu$ is shown to be unstable due to resonance between orbital and internal frequencies if $\frac{M}{d^3} < \frac{4}{3} \pi \rho < \frac{ M + 3 m \left( 1+\mu/M \right)^{-1}}{d^3}$, where $\rho$ is the central density of mass $M$, and $d$ distance between masses $m$ and $M$ (circular orbit diameter). The above result is important for core-collapse supernova theory, with mass $\mu$ identified with helium core of the exploding massive star. The instability cause off-center supernova "ignition" relative to the center-of-mass of the hydrogen envelope. The instability is also inevitable during protoplanet growth, with hypothetical ejection of the rocky core from gas giants and formation of the "puffy planets" due to resonance with orbital frequency. Hypothetical central intermediate black holes of the globular clusters are also in unstable position with respect to perturbations caused by the Galaxy.Comment: re-submitted to MNRA