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...
Study of the preheating phase of chaotic inflation (2008)
Anderson, Paul R., Molina-Paris, Carmen, Evanich, David, Cook, Gregory B.
Particle production and its effects on the inflaton field are investigated during the preheating phase of chaotic inflation using a model consisting of a massive scalar inflaton field coupled to N...
High-accuracy comparison of numerical relativity simulations with post-Newtonian expansions (2007)
Boyle, Michael, Brown, Duncan A., Kidder, Lawrence E., Mroué, Abdul H., Pfeiffer, Harald P., Scheel, Mark A., ...
Numerical simulations of 15 orbits of an equal-mass binary black-hole system are presented. Gravitational waveforms from these simulations, covering more than 30 cycles and ending about 1.5 cycles...
High-accuracy comparison of numerical relativity simulations with post-Newtonian expansions (2007)
Boyle, Michael, Brown, Duncan A., Kidder, Lawrence E., Mroue, Abdul H., Pfeiffer, Harald P., Scheel, Mark A., ...
Numerical simulations of 15 orbits of an equal-mass binary black hole system are presented. Gravitational waveforms from these simulations, covering more than 30 cycles and ending about 1.5 cycles...
Measuring eccentricity in binary black-hole initial data (2007)
Grigsby, Jason D., Cook, Gregory B.
Initial data for evolving black-hole binaries can be constructed via many techniques, and can represent a wide range of physical scenarios. However, because of the way that different schemes...
Approximate Killing Vectors on S^2 (2007)
Cook, Gregory B., Whiting, Bernard F.
We present a new method for computing the best approximation to a Killing vector on closed 2-surfaces that are topologically S^2. When solutions of Killing's equation do not exist, this method is...
Inspiral, merger and ring-down of equal-mass black-hole binaries (2006)
Buonanno, Alessandra, Cook, Gregory B., Pretorius, Frans
We investigate the dynamics and gravitational-wave (GW) emission in the binary merger of equal-mass black holes as obtained from numerical relativity simulations. Results from the evolution of three...
Circular orbits and spin in black-hole initial data (2006)
Caudill, Matthew, Cook, Gregory B., Grigsby, Jason D., Pfeiffer, Harald P.
The construction of initial data for black-hole binaries usually involves the choice of free parameters that define the spins of the black holes and essentially the eccentricity of the orbit. Such...
Circular orbits and spin in black-hole initial data (2006)
Caudill, Matthew, Cook, Gregory B., Grigsby, Jason D., Pfeiffer, Harald P.
The construction of initial data for black-hole binaries usually involves the choice of free parameters that define the spins of the black holes and essentially the eccentricity of the orbit. Such...
Conformal thin-sandwich puncture initial data for boosted black holes (2005)
Hannam, Mark D., Cook, Gregory B.
We apply the puncture approach to conformal thin-sandwich black-hole initial data. We solve numerically the conformal thin-sandwich puncture (CTSP) equations for a single black hole with non-zero...
Excision boundary conditions for black-hole initial data (2004)
Cook, Gregory B., Pfeiffer, Harald P.
We define and extensively test a set of boundary conditions that can be applied at black-hole excision surfaces when the Hamiltonian and momentum constraints of general relativity are solved within...
Excision boundary conditions for black hole initial data (2004)
Cook, Gregory B., Pfeiffer, Harald P.
We define and extensively test a set of boundary conditions that can be applied at black hole excision surfaces when the Hamiltonian and momentum constraints of general relativity are solved within...
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...
Comparing initial-data sets for binary black holes (2002)
Pfeiffer, Harald P., Cook, Gregory B., Teukolsky, Saul A.
We compare the results of constructing binary black hole initial data with three different decompositions of the constraint equations of general relativity. For each decomposition we compute the...
In the first of two talks on the computation of initial data, we will look at some of the formalisms used for posing the constraint equations of general relativity as a boundary-value problem. This...
Corotating and irrotational binary black holes in quasi-circular orbits (2001)
A complete formalism for constructing initial data representing black-hole binaries in quasi-equilibrium is developed. Radiation reaction prohibits, in general, true equilibrium binary...
Initial Data for Numerical Relativity (2000)
Initial data are the starting point for any numerical simulation. In the case of numerical relativity, Einstein's equations constrain our choices of these initial data. We will examine several of the...
Quasi-circular Orbits for Spinning Binary Black Holes (2000)
Pfeiffer, Harald P., Teukolsky, Saul A., Cook, Gregory B.
Using an effective potential method we examine binary black holes where the individual holes carry spin. We trace out sequences of quasi-circular orbits and locate the innermost stable circular orbit...
Black hole evolution by spectral methods (2000)
Kidder, Lawrence E., Scheel, Mark A., Teukolsky, Saul A., Carlson, Eric D., Cook, Gregory B.
Current methods of evolving a spacetime containing one or more black holes are plagued by instabilities that prohibit long-term evolution. Some of these instabilities may be due to the numerical...
Roles of Hyperons in Neutron Stars (1998)
Balberg, Shmuel, Lichtenstadt, Itamar, Cook, Gregory. B.
We examine the roles the presence of hyperons in the cores of neutron stars may play in determining global properties of these stars. The study is based on estimates that hyperons appear in neutron...
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...
Miller, M. Coleman, Lamb, Frederick K., Cook, Gregory B.
Quasi-periodic X-ray brightness oscillations (QPOs) with frequencies around a kilohertz have now been discovered in more than a dozen neutron stars in low-mass X-ray binary systems using the Rossi...
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...
Testing a Simplified Version of Einstein's Equations for Numerical Relativity (1995)
Cook, Gregory B., Shapiro, Stuart L., Teukolsky, Saul A.
Solving dynamical problems in general relativity requires the full machinery of numerical relativity. Wilson has proposed a simpler but approximate scheme for systems near equilibrium, like binary...
Collisions of boosted black holes: perturbation theory prediction of gravitational radiation (1994)
Abrahams, Andrew M., Cook, Gregory B.
We consider general relativistic Cauchy data representing two nonspinning, equal-mass black holes boosted toward each other. When the black holes are close enough to each other and their momentum is...
The construction of initial-data sets representing binary black-hole configurations in quasi-circular orbits is studied in the context of the conformal-imaging formalism. An effective-potential...
Initial data for the two-body problem of general relativity /--by Gregory B. Cook. (1990)
Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 1990.