Paschalidis, Vasileios, MacLeod, Morgan, Baumgarte, Thomas W., Shapiro, Stuart L.
White dwarf-neutron star binaries generate detectable gravitational radiation. We construct Newtonian equilibrium models of corotational white dwarf-neutron star (WDNS) binaries in circular orbit and...
A formalism for the construction of binary neutron stars with arbitrary circulation (2009)
Baumgarte, Thomas W., Shapiro, Stuart L.
Most numerical models of binary stars - in particular neutron stars in compact binaries - assume the companions to be either corotational or irrotational. Either one of these assumptions leads to a...
Trumpet-puncture initial data for black holes (2009)
Immerman, Jason D., Baumgarte, Thomas W.
We propose a new approach, based on the puncture method, to construct black hole initial data in the so-called trumpet geometry, i.e. on slices that asymptote to a limiting surface of non-zero areal...
Relativistic Simulations of Black Hole-Neutron Star Mergers: Effects of black-hole spin (2008)
Etienne, Zachariah B., Liu, Yuk Tung, Shapiro, Stuart L., Baumgarte, Thomas W.
Black hole-neutron star (BHNS) binary mergers are candidate engines for generating both short-hard gamma-ray bursts (SGRBs) and detectable gravitational waves. Using our most recent conformal...
Excision boundary conditions for the conformal metric (2008)
Cook, Gregory B., Baumgarte, Thomas W.
Shibata, Ury\=u and Friedman recently suggested a new decomposition of Einstein's equations that is useful for constructing initial data. In contrast to previous decompositions, the conformal metric...
Fully General Relativistic Simulations of Black Hole-Neutron Star Mergers (2007)
Etienne, Zachariah B., Faber, Joshua A., Liu, Yuk Tung, Shapiro, Stuart L., Taniguchi, Keisuke, Baumgarte, Thomas W.
Black hole-neutron star (BHNS) binaries are expected to be among the leading sources of gravitational waves observable by ground-based detectors, and may be the progenitors of short-hard gamma ray...
Matera, Keith, Baumgarte, Thomas W., Gourgoulhon, Eric
We solve Einstein's constraint equations in the conformal thin-sandwich decomposition to model thin shells of non-interacting particles in circular orbit about a non-rotating black hole. We use these...
Taniguchi, Keisuke, Baumgarte, Thomas W., Faber, Joshua A., Shapiro, Stuart L.
We construct new models of black hole-neutron star binaries in quasiequilibrium circular orbits by solving Einstein's constraint equations in the conformal thin-sandwich decomposition together with...
Relativistic hydrodynamics in the presence of puncture black holes (2007)
Faber, Joshua A., Baumgarte, Thomas W., Etienne, Zachariah B., Shapiro, Stuart L., Taniguchi, Keisuke
Many of the recent numerical simulations of binary black holes in vacuum adopt the moving puncture approach. This successful approach avoids the need to impose numerical excision of the black hole...
Filling the holes: Evolving excised binary black hole initial data with puncture techniques (2007)
Etienne, Zachariah B., Faber, Joshua A., Liu, Yuk Tung, Shapiro, Stuart L., Baumgarte, Thomas W.
We follow the inspiral and merger of equal-mass black holes (BHs) by the moving puncture technique and demonstrate that both the exterior solution and the asymptotic gravitational waveforms are...
Einstein constraints: Uniqueness and nonuniqueness in the conformal thin sandwich approach (2007)
Baumgarte, Thomas W., Murchadha, Niall Ó, Pfeiffer, Harald P.
We study the appearance of multiple solutions to certain decompositions of Einstein's constraint equations. Pfeiffer and York recently reported the existence of two branches of solutions for a...
Quasiequilibrium black hole-neutron star binaries in general relativity (2007)
Taniguchi, Keisuke, Baumgarte, Thomas W., Faber, Joshua A., Shapiro, Stuart L.
We construct quasiequilibrium sequences of black hole-neutron star binaries in general relativity. We solve Einstein's constraint equations in the conformal thin-sandwich formalism, subject to black...
Analytical Representation of a Black Hole Puncture Solution (2007)
Baumgarte, Thomas W., Naculich, Stephen G.
The ``moving puncture'' technique has led to dramatic advancements in the numerical simulations of binary black holes. Hannam et.al. have recently demonstrated that, for suitable gauge conditions...
Baumgarte, Thomas W., Murchadha, Niall Ó, Pfeiffer, Harald P.
We study the appearance of multiple solutions to certain decompositions of Einstein's constraint equations. Pfeiffer and York recently reported the existence of two branches of solutions for...
Approximate initial data for binary black holes (2006)
Dennison, Kenneth A., Baumgarte, Thomas W., Pfeiffer, Harald P.
We construct approximate analytical solutions to the constraint equations of general relativity for binary black holes of arbitrary mass ratio in quasicircular orbit. We adopt the puncture method to...
Quasiequilibrium sequences of black-hole--neutron-star binaries in general relativity (2006)
Taniguchi, Keisuke, Baumgarte, Thomas W., Faber, Joshua A., Shapiro, Stuart L.
We construct quasiequilibrium sequences of black hole-neutron star binaries for arbitrary mass ratios by solving the constraint equations of general relativity in the conformal thin-sandwich...
Approximate initial data for binary black holes (2006)
Dennison, Kenneth A., Baumgarte, Thomas W., Pfeiffer, Harald P.
We construct approximate analytical solutions to the constraint equations of general relativity for binary black holes of arbitrary mass ratio in quasicircular orbit. We adopt the puncture method to...
Faber, Joshua A., Baumgarte, Thomas W., Shapiro, Stuart L., Taniguchi, Keisuke, Rasio, Frederic A.
We have calculated the first dynamical evolutions of merging black hole-neutron star binaries that treat the combined spacetime in a nonperturbative general relativistic framework. Using the...
Black Holes: from Speculations to Observations (2006)
This paper provides a brief review of the history of our understanding and knowledge of black holes. Starting with early speculations on ``dark stars'' I discuss the Schwarzschild "black hole"...
General Relativistic Binary Merger Simulations and Short Gamma Ray Bursts (2006)
Faber, Joshua A., Baumgarte, Thomas W., Shapiro, Stuart L., Taniguchi, Keisuke
The recent localization of some short-hard gamma ray bursts (GRBs) in galaxies with low star formation rates has lent support to the suggestion that these events result from compact object binary...
Faber, Joshua A., Baumgarte, Thomas W., Shapiro, Stuart L., Taniguchi, Keisuke, Rasio, Frederic A.
We calculate the first dynamical evolutions of merging black hole-neutron star binaries that construct the combined black hole-neutron star spacetime in a general relativistic framework. We treat the...
Black hole-neutron star binaries in general relativity: effects of neutron star spin (2005)
Taniguchi, Keisuke, Baumgarte, Thomas W., Faber, Joshua A., Shapiro, Stuart L.
We present new sequences of general relativistic, quasiequilibrium black hole-neutron star binaries. We solve for the gravitational field in the conformal thin-sandwich decomposition of Einstein's...
Burko, Lior M., Baumgarte, Thomas W., Beetle, Christopher
Beetle and Burko recently introduced a background--independent scalar curvature invariant for general relativity that carries information only about the gravitational radiation in generic spacetimes,...
Quasi-equilibrium Binary Black Hole Initial Data for Dynamical Evolutions (2004)
Yo, Hwei-Jang, Cook, James N., Shapiro, Stuart L., Baumgarte, Thomas W.
We present a formalism for constructing quasi-equilibrium binary black hole initial data suitable for numerical evolution. We construct quasi-equilibrium models by imposing an approximate helical...
Black Hole-Neutron Star Binaries in General Relativity: Quasiequilibrium Formulation (2004)
Baumgarte, Thomas W., Skoge, Monica L., Shapiro, Stuart L.
We present a new numerical method for the construction of quasiequilibrium models of black hole-neutron star binaries. We solve the constraint equations of general relativity, decomposed in the...
Morrison, Ian A., Baumgarte, Thomas W., Shapiro, Stuart L.
The merger of binary neutron stars is likely to lead to differentially rotating remnants. In this paper, we survey several cold nuclear equations of state (EOSs) and numerically construct models of...
Dynamical Determination of the Innermost Stable Circular Orbit of Binary Neutron Stars (2003)
Marronetti, Pedro, Duez, Matthew D., Shapiro, Stuart L., Baumgarte, Thomas W.
We determine the innermost stable circular orbit (ISCO) of binary neutron stars (BNSs) by performing dynamical simulations in full general relativity. Evolving quasiequilibrium (QE) binaries that...
Hannam, Mark D., Evans, Charles R., Cook, Gregory B., Baumgarte, Thomas W.
We consider combining two important methods for constructing quasi-equilibrium initial data for binary black holes: the conformal thin-sandwich formalism and the puncture method. The former seeks to...
One-Armed Spiral Instability in Differentially Rotating Stars (2003)
Saijo, Motoyuki, Baumgarte, Thomas W., Shapiro, Stuart L.
We investigate the dynamical instability of the one-armed spiral m=1 mode in differentially rotating stars by means of 3+1 hydrodynamical simulations in Newtonian gravitation. We find that both a...
One-armed spiral instability in differentially rotating stars (2003)
Saijo, Motoyuki, Baumgarte, Thomas W., Shapiro, Stuart L.
We investigate the dynamical instability of the one-armed spiral m=1 mode in differentially rotating stars by means of 3+1 hydrodynamical simulations in Newtonian gravitation. We find that both a...
Collapse of a Magnetized Star to a Black Hole (2002)
Baumgarte, Thomas W., Shapiro, Stuart L.
We study of the collapse of a magnetized spherical star to a black hole in general relativity theory. The matter and gravitational fields are described by the exact Oppenheimer-Snyder solution for...
General-Relativistic MHD for the Numerical Construction of Dynamical Spacetimes (2002)
Baumgarte, Thomas W., Shapiro, Stuart L.
We assemble the equations of general relativistic magnetohydrodynamics (MHD) in 3+1 form. These consist of the complete coupled set of Maxwell equations for the electromagnetic field, Einstein's...
Numerical Relativity and Compact Binaries (2002)
Baumgarte, Thomas W., Shapiro, Stuart L.
Numerical relativity is the most promising tool for theoretically modeling the inspiral and coalescence of neutron star and black hole binaries, which, in turn, are among the most promising sources...
Comparing Criteria for Circular Orbits in General Relativity (2002)
Skoge, Monica L., Baumgarte, Thomas W.
We study a simple analytic solution to Einstein's field equations describing a thin spherical shell consisting of collisionless particles in circular orbit. We then apply two independent criteria for...
Effects of Differential Rotation on the Maximum Mass of Neutron Stars (2002)
Lyford, Nicholas D., Baumgarte, Thomas W., Shapiro, Stuart L.
The merger of binary neutron stars is likely to lead to differentially rotating remnants. In this paper we numerically construct models of differentially rotating neutron stars in general relativity...
Hydrodynamic Simulations in 3+1 General Relativity (2002)
Duez, Matthew D., Marronetti, Pedro, Shapiro, Stuart L., Baumgarte, Thomas W.
We solve Einstein's field equations coupled to relativistic hydrodynamics in full 3+1 general relativity to evolve astrophysical systems characterized by strong gravitational fields. We model...
Improved numerical stability of stationary black hole evolution calculations (2002)
Yo, Hwei-Jang, Baumgarte, Thomas W., Shapiro, Stuart L.
We experiment with modifications of the BSSN form of the Einstein field equations (a reformulation of the ADM equations) and demonstrate how these modifications affect the stability of numerical...
Saijo, Motoyuki, Baumgarte, Thomas W., Shapiro, Stuart L., Shibata, Masaru
We study the gravitational collapse of a rotating supermassive star (SMS) by means of a (3+1) hydrodynamical simulation in a post-Newtonian (PN) approxi- mation of general relativity. This problem is...
Saijo, Motoyuki, Baumgarte, Thomas W., Shapiro, Stuart L., Shibata, Masaru
We study the gravitational collapse of a rotating supermassive star (SMS) by means of a (3+1) hydrodynamical simulation in a post-Newtonian (PN) approxi- mation of general relativity. This problem is...
Comparing the inspiral of irrotational and corotational binary neutron stars (2001)
Duez, Matthew D., Baumgarte, Thomas W., Shapiro, Stuart L., Shibata, Masaru, Uryu, Koji
We model the adiabatic inspiral of relativistic binary neutron stars in a quasi-equilibrium (QE) approximation, and compute the gravitational wavetrain from the late phase of the inspiral. We compare...
Dynamical Bar Instability in Relativistic Rotating Stars (2001)
Saijo, Motoyuki, Shibata, Masaru, Baumgarte, Thomas W., Shapiro, Stuart L.
We study by computational means the dynamical stability against bar-mode deformation of rapidly and differentially rotating stars in a post-Newtonian approximation of general relativity. We vary the...
The Innermost Stable Circular Orbit in Compact Binaries (2001)
Newtonian point mass binaries can be brought into arbitrarily close circular orbits. Neutron stars and black holes, however, are extended, relativistic objects. Both finite size and relativistic...
Dynamical bar instability in rotating stars: effect of general relativity (2001)
Saijo, Motoyuki, Shibata, Masaru, Baumgarte, Thomas W., Shapiro, Stuart L.
We study the dynamical stability against bar-mode deformation of rapidly and differentially rotating stars in the first post-Newtonian approximation of general relativity. We vary the compaction of...
Yo, Hwei-Jang, Baumgarte, Thomas W., Shapiro, Stuart L.
A quasi-equilibrium (QE) computational scheme was recently developed in general relativity to calculate the complete gravitational wavetrain emitted during the inspiral phase of compact binaries. The...
Dynamical Bar Instability in Rotating Stars: Effect of General Relativity (2000)
Saijo, Motoyuki, Shibata, Masaru, Baumgarte, Thomas W., Shapiro, Stuart L.
We study the dynamical stability against bar-mode deformation of rapidly and differentially rotating stars in the first post-Newtonian approximation of general relativity. We vary the compaction of...
Computing the Complete Gravitational Wavetrain from Relativistic Binary Inspiral (2000)
Duez, Matthew D., Baumgarte, Thomas W., Shapiro, Stuart L.
We present a new method for generating the nonlinear gravitational wavetrain from the late inspiral (pre-coalescence) phase of a binary neutron star system by means of a numerical evolution...
Radiative Falloff in Neutron Star Spacetimes (2000)
Pavlidou, Vasiliki, Tassis, Konstantinos, Baumgarte, Thomas W., Shapiro, Stuart L.
We systematically study late-time tails of scalar waves propagating in neutron star spacetimes. We consider uniform density neutron stars, for which the background spacetime is analytic and the...
Shibata, Masaru, Baumgarte, Thomas W., Shapiro, Stuart L.
We study the dynamical stability against bar-mode deformation of rapidly spinning neutron stars with differential rotation. We perform fully relativistic 3D simulations of compact stars with $M/R...
The Innermost Stable Circular Orbit of Binary Black Holes (2000)
We introduce a new method to construct solutions to the constraint equations of general relativity describing binary black holes in quasicircular orbit. Black hole pairs with arbitrary momenta can be...
Shibata, Masaru, Baumgarte, Thomas W., Shapiro, Stuart L.
We perform 3D numerical simulations in full general relativity to study the stability of rapidly rotating, supramassive neutron stars at the mass-shedding limit to dynamical collapse. We adopt an...
On the Maximum Mass of Differentially Rotating Neutron Stars (1999)
Baumgarte, Thomas W., Shapiro, Stuart L., Shibata, Masaru
We construct relativistic equilibrium models of differentially rotating neutron stars and show that they can support significantly more mass than their nonrotating or uniformly rotating counterparts....
Luminosity versus Rotation in a Supermassive Star (1999)
Baumgarte, Thomas W., Shapiro, Stuart L.
We determine the effect of rotation on the luminosity of supermassive stars. We apply the Roche model to calculate analytically the emitted radiation from a uniformly rotating, radiation-dominated...
Evolution of Rotating Supermassive Stars to the Onset of Collapse (1999)
Baumgarte, Thomas W., Shapiro, Stuart L.
We launch a fully relativistic study of the formation of supermassive black holes via the collapse of supermassive stars. Here we initiate our investigation by analyzing the secular evolution of...
Evolving Einstein's Field Equations with Matter: The ``Hydro without Hydro'' Test (1999)
Baumgarte, Thomas W., Hughes, Scott A., Shapiro, Stuart L.
We include matter sources in Einstein's field equations and show that our recently proposed 3+1 evolution scheme can stably evolve strong-field solutions. We insert in our code known matter...
On the Numerical Integration of Einstein's Field Equations (1998)
Baumgarte, Thomas W., Shapiro, Stuart L.
Many numerical codes now under development to solve Einstein's equations of general relativity in 3+1 dimensional spacetimes employ the standard ADM form of the field equations. This form involves...
Treating instabilities in a hyperbolic formulation of Einstein's equations (1998)
Scheel, Mark A., Baumgarte, Thomas W., Cook, Gregory B., Shapiro, Stuart L., Teukolsky, Saul A.
We have recently constructed a numerical code that evolves a spherically symmetric spacetime using a hyperbolic formulation of Einstein's equations. For the case of a Schwarzschild black hole, this...
Radiation of Angular Momentum by Neutrinos from Merged Binary Neutron Stars (1998)
Baumgarte, Thomas W., Shapiro, Stuart L.
We study neutrino emission from the remnant of an inspiraling binary neutron star following coalescence. The mass of the merged remnant is likely to exceed the stability limit of a cold, rotating...
Numerical Evolution of Black Holes with a Hyperbolic Formulation of General Relativity (1997)
Scheel, Mark A., Baumgarte, Thomas W., Cook, Gregory B., Shapiro, Stuart L., Teukolsky, Saul A.
We describe a numerical code that solves Einstein's equations for a Schwarzschild black hole in spherical symmetry, using a hyperbolic formulation introduced by Choquet-Bruhat and York. This is the...
Binary Neutron Stars in Quasi-Equilibrium Circular Orbit: A Fully Relativistic Treatment (1997)
Baumgarte, Thomas W., Shapiro, Stuart L., Cook, Gregory B., Scheel, Mark A., Teukolsky, Saul A.
We present a numerical scheme that solves the initial value problem in full general relativity for a binary neutron star in quasi-equilibrium. While Newtonian gravity allows for a strict equilibrium,...
Implementing an apparent-horizon finder in three dimensions (1996)
Baumgarte, Thomas W., Cook, Gregory B., Scheel, Mark A., Shapiro, Stuart L., Teukolsky, Saul A.
Locating apparent horizons is not only important for a complete understanding of numerically generated spacetimes, but it may also be a crucial component of the technique for evolving black-hole...