We describe a numerical method for calculating the (3+1)-dimensional general relativistic hydrodynamics of coalescing neutron-star binary system. The field equations are solved at each time slice with spatial three-metric chosen to be conformally flat. Against this solution equations, hydrodynamic variables and gravitational radiation allowed respond. signal is derived via multipole expansion metric perturbation hexadecapole ($l=4$) order including both mass current moments correction...

We use heavy element nucleosynthesis from supernovae to probe the mixing of ${\ensuremath{\nu}}_{\mathit{e}}$ with ${\ensuremath{\nu}}_{\mathrm{\ensuremath{\tau}}}$ (or ${\ensuremath{\nu}}_{\mathrm{\ensuremath{\mu}}}$) possessing cosmologically significant masses (1 100 eV). conclude that ${\ensuremath{\nu}}_{\mathrm{\ensuremath{\tau}}}$(${\ensuremath{\nu}}_{\mathrm{\ensuremath{\mu}}}$)-${\ensuremath{\nu}}_{\mathit{e}}$ vacuum angle must satisfy...

We report on a new analysis of instabilities in close neutron star binaries based upon (3 + 1) dimensional general relativistic numerical hydrodynamics calculations. When realistic equation state is employed, orbit calculations for two $1.45{M}_{\ensuremath{\bigodot}}$ stars reveal surprising evidence that effects may cause otherwise stable to individually collapse prior merging. Also, the strong fields last occur at larger separation distance and lower frequency than post-Newtonian estimates.

We report on a study of the natural warm inflationary paradigm (WNI). show two important new results arise in this model. One is that observational constraints primordial power spectrum from cosmic microwave background (CMB) can be satisfied without going beyond Planck scale effective field theory. The second WNI inevitably provide perfect conditions for production black holes (PBHs) golden window black-hole mass range ($10^{-16} -10^{-11}M_{\odot}$) where it account all dark matter content...

We present the results of detailed nuclear shell model calculations spin-dependent elastic cross section for neutralinos scattering from \si29 and \ge73. The were performed in large spaces which adequately describe configuration mixing these two nuclei. As tests computed wave functions, we have calculated several observables compared them with measured values found good agreement. In limit zero momentum transfer, find matrix elements agreement previous estimates but significantly different...

We discuss a cosmology in which cold dark matter particles decay into relativistic particles. argue that such decays could lead naturally to bulk viscosity the cosmic fluid. For lifetimes comparable present Hubble age, this enters energy equation as an effective negative pressure. investigate whether pressure is of sufficient magnitude account for observed acceleration. show single decaying species $\ensuremath{\Lambda}=0$, flat, dark-matter dominated can not reproduce magnitude-redshift...

It is anticipated that the gravitational radiation detected in future wave (GW) detectors from binary neutron star (NS) mergers can probe high-density equation of state (EOS). We perform first simulations NS which adopt various parametrizations quark-hadron crossover (QHC) EOS. These are constructed combinations a hadronic EOS (${n}_{b}<2\text{ }\text{ }{n}_{0}$) and quark-matter (${n}_{b}>5\text{ }{n}_{0}$), where ${n}_{b}$ ${n}_{0}$ baryon number density nuclear saturation density,...

We have made core-collapse supernova simulations that allow oscillations between electron neutrinos (or their anti particles) with right-handed sterile neutrinos. considered a range of mixing angles and neutrino masses including those consistent as dark matter candidate. examine whether such can impact the core bounce shock reheating in supernovae. identify optimum ranges dramatically enhance explosion by efficiently transporting anti-neutrinos from to behind where they provide additional...

Neutron stars with very strong surface magnetic fields have been suggested as the site for origin of observed soft gamma repeaters (SGRs). In this paper we investigate influence such on properties and internal structure these strongly magnetized neutron (magnetars). We study a degenerate equilibrium ideal neutron-proton-electron (npe) gas without effects anomalous nucleon moment in field. The presence sufficiently field changes ratio protons to neutrons well drip density. also appearance...

We report on numerical results from an independent formalism to describe the quasi-equilibrium structure of nonsynchronous binary neutron stars in general relativity. This is important test controversial hydrodynamic simulations which suggested that a close can experience compression prior last stable circular orbit. show that, for compact enough interior density increases slightly as irrotational approach their orbits. The magnitude effect, however, much smaller than reported previous simulations.

We have reconstructed possible orbits for a collection of stars located within 05 Sgr A*. These are constrained by observed stellar positions and angular proper motions. The construction such serves as baseline from which to search deviations due the unseen mass distribution in central 1000 AU Galaxy. also discuss likelihood that some these may eventually exhibit detectable relativistic effects, allowing interesting tests general relativity around 2.6 × 106 M☉ object.

Recently, several white dwarfs with very strong surface magnetic fields have been observed. In this paper we explore the possibility that such stars could sufficiently internal to alter their structure. We obtain a revised dwarf mass-radius relation in presence of fields. first derive equation state for fully degenerate ideal electron gas field using an Euler-MacLaurin expansion. use 4He, 12C, and 56Fe uniform composition.

We report on numerical results from a revised hydrodynamic simulation of binary neutron-star orbits near merger. find that the correction recently identified by Flanagan significantly reduces but does not eliminate compression effect. Although simulations show is reduced for given total orbital angular momentum, inner most stable circular orbit moves to closer separation distances. At these significant and even collapse are still possible prior merger sufficiently soft EOS. note, however,...

A global study of the mass, energy, and angular distributions all products formed in collisions 180-MeV protons with $^{27}\mathrm{Al}$ is reported. These data are compared calculations based on intranuclear-cascade-plus-evaporation, preequilibrium hybrid, semiempirical models. It found that there evidence for enhanced energy deposition nucleon-nucleus relative to predictions intranuclear cascade calculations. In contrast, produce stronger damping, more consistent observed data.

Recently, attempts have been made to understand the apparent near coincidence of present dark energy and matter in terms a dynamical attractor-like solution for evolution ``quintessence'' scalar field. In these models field couples with dominant constituent only acts like cosmological constant after onset matter-dominated epoch. A generic feature such solutions, however, is possibility significant density during radiation-dominated This even greater if quintessence begins kinetic-dominated...

We discuss a cosmology in which cold dark matter begins to decay into relativistic particles at recent epoch ($z<1$). show that the large entropy production and associated bulk viscosity from such decays leads an accelerating as required by observations. investigate effects of decaying $\ensuremath{\Lambda}=0$, flat, initially dominated cosmology. this model satisfies cosmological constraint redshift-distance relation for type Ia supernovae. The age models is also consistent with constraints...

We analyze the spectrum of gravitational waves generated by induced tensor fluctuation during warm natural inflation. In our previous work, it has been demonstrated that an epoch inflation can lead to cosmologically relevant dark matter production in form primordial black holes. Here, we show models solve dark-matter also produce a contribution cosmic wave background satisfies current constraints from pulsar timing and big bang nucleosynthesis. More importantly, this may be observable next...

We discuss the underlying relativistic physics which causes neutron stars to compress and collapse in close binary systems as has recently been observed numerical (3+1) dimensional general hydrodynamic simulations. show that compression is driven by velocity-dependent terms increase self gravity of stars. They also produce fluid motion with respect corotating frame binary. present analytic results confirm such are insignificant for uniform translation or when hydrodynamics constrained rigid...

We explore observational constraints on a cosmological brane world scenario in which the bulk is not empty. Rather, exchange of mass energy between and allowed. The evolution matter fields to an observer then modified due new terms energy-momentum tensor describing this exchange. investigate from various observations flow into brane. Interestingly, we show that it possible have $\ensuremath{\Lambda}=0$ cosmology satisfies standard including cosmic microwave background (CMB) temperature...

Abstract We study the evolution of rapid neutron-capture process (r-process) isotopes in galaxy. analyze relative contributions from core-collapse supernovae (CCSNe), neutron star mergers, and collapsars under a range astrophysical conditions nuclear input data. Here we show that, although r-process each these sites can lead to similar (universal) elemental distribution, detailed isotopic abundances differ one site another. These differences may allow for identification which sources...