Sascha Husa

Testing gravitational-wave searches with numerical relativity waveforms: results from the first Numerical INJection Analysis (NINJA) project (2009)

Aylott, Benjamin, Baker, John G., Boggs, William D., Boyle, Michael, Brady, Patrick R., Brown, Duncan A., ...

The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave data analysis communities. The purpose of NINJA is to...

Bowen-York trumpet data and black-hole simulations (2009)

Hannam, Mark, Husa, Sascha, Murchadha, Niall Ó

The most popular method to construct initial data for black-hole-binary simulations is the puncture method, in which compactified wormholes are given linear and angular momentum via the Bowen-York...

Gravitational-wave detectability of equal-mass black-hole binaries with aligned spins (2009)

Reisswig, Christian, Husa, Sascha, Rezzolla, Luciano, Dorband, Ernst Nils, Pollney, Denis, Seiler, Jennifer

Binary black-hole systems with spins aligned or anti-aligned to the orbital angular momentum provide the natural ground to start detailed studies of the influence of strong-field spin effects on...

Status of NINJA: the Numerical INJection Analysis project (2009)

Cadonati, Laura, Aylott, Benjamin, Baker, John G., Boggs, William D., Boyle, Michael, Brady, Patrick R., ...

The 2008 NRDA conference introduced the Numerical INJection Analysis project (NINJA), a new collaborative effort between the numerical relativity community and the data analysis community. NINJA...

Status of NINJA: the Numerical INJection Analysis project (2009)

Aylott, Benjamin, Baker, John G., Boggs, William D., Boyle, Michael, Brady, Patrick R., Brown, Duncan A., ...

The 2008 NRDA conference introduced the Numerical INJection Analysis project (NINJA), a new collaborative effort between the numerical relativity community and the data analysis community. NINJA...

Stationary hyperboloidal slicings with evolved gauge conditions (2009)

Ohme, Frank, Hannam, Mark, Husa, Sascha, Murchadha, Niall Ó

We analyze stationary slicings of the Schwarzschild spacetime defined by members of the Bona-Masso family of slicing conditions. Our main focus is on the influence of a non-vanishing offset to the...

Samurai project: Verifying the consistency of black-hole-binary waveforms for gravitational-wave detection (2009)

Hannam, Mark, Husa, Sascha, Baker, John G., Boyle, Michael, Brügmann, Bernd, Chu, Tony, ...

We quantify the consistency of numerical-relativity black-hole-binary waveforms for use in gravitational-wave (GW) searches with current and planned ground-based detectors. We compare previously...

Testing gravitational-wave searches with numerical relativity waveforms: Results from the first Numerical INJection Analysis (NINJA) project (2009)

Aylott, Benjamin, Baker, John G., Boggs, William D., Boyle, Michael, Brady, Patrick R., Brown, Duncan A., ...

The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave data analysis communities. The purpose of NINJA is to...

The Samurai Project: verifying the consistency of black-hole-binary waveforms for gravitational-wave detection (2009)

Hannam, Mark, Husa, Sascha, Baker, John G., Boyle, Michael, Bruegmann, Bernd, Chu, Tony, ...

We quantify the consistency of numerical-relativity black-hole-binary waveforms for use in gravitational-wave (GW) searches with current and planned ground-based detectors. We compare previously...

Gravitational perturbations of Schwarzschild spacetime at null infinity and the hyperboloidal initial value problem (2009)

Zenginoglu, Anil, Nunez, Dario, Husa, Sascha

We study gravitational perturbations of Schwarzschild spacetime by solving a hyperboloidal initial value problem for the Bardeen-Press equation. Compactification along hyperboloidal surfaces in a...

Testing gravitational-wave searches with numerical relativity waveforms: Results from the first Numerical INJection Analysis (NINJA) project (2009)

Aylott, Benjamin, Baker, John G., Boggs, William D., Boyle, Michael, Brady, Patrick R., Brown, Duncan A., ...

The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave data analysis communities. The purpose of NINJA is to...

Stationary hyperboloidal slicings with evolved gauge conditions (2009)

Ohme, Frank, Hannam, Mark, Husa, Sascha, Ó Murchadha, Niall

We analyze stationary slicings of the Schwarzschild spacetime defined by members of the Bona-Masso family of slicing conditions. Our main focus is on the influence of a non-vanishing offset to the...

Numerical modeling of black holes as sources of gravitational waves in a nutshell (2008)

Husa, Sascha

These notes summarize basic concepts underlying numerical relativity and in particular the numerical modeling of black hole dynamics as a source of gravitational waves. Main topics are the 3+1...

Gravitational perturbations of Schwarzschild spacetime at null infinity and the hyperboloidal initial value problem (2008)

Zenginoglu, Anil, Nunez, Dario, Husa, Sascha

We study gravitational perturbations of Schwarzschild spacetime by solving a hyperboloidal initial value problem for the Bardeen-Press equation. Compactification along hyperboloidal surfaces in a...

Final spin from the coalescence of two black holes (2008)

Rezzolla, Luciano, Barausse, Enrico, Dorband, Ernst Nils, Pollney, Denis, Reisswig, Christian, Seiler, Jennifer, ...

We provide a compact analytic formula to compute the spin of the black hole produced by the coalescence of two black holes following a quasicircular inspiral. Without additional fits than those...

Resolving Super Massive Black Holes with LISA (2008)

Babak, Stanislav, Hannam, Mark, Husa, Sascha, Schutz, Bernard

We study the angular resolution of the gravitational wave detector LISA and show that numerical relativity can drastically improve the accuracy of position location for coalescing Super Massive Black...

Wormholes and trumpets: the Schwarzschild spacetime for the moving-puncture generation (2008)

Hannam, Mark, Husa, Sascha, Ohme, Frank, Bruegmann, Bernd, O'Murchadha, Niall

We expand upon our previous analysis of numerical moving-puncture simulations of the Schwarzschild spacetime. We present a derivation of the family of analytic stationary 1+log foliations of the...

Accurate Effective-One-Body waveforms of inspiralling and coalescing black-hole binaries (2008)

Damour, Thibault, Nagar, Alessandro, Hannam, Mark, Husa, Sascha, Brugmann, Bernd

The Effective-One-Body (EOB) formalism contains several flexibility parameters, notably $a_5$, $\vp$ and $\a$. We show here how to jointly constrain the values of these parameters by simultaneously...

Hyperboloidal foliations with scri-fixing in spherical symmetry (2008)

Zenginoglu, Anil, Husa, Sascha

We study in spherical symmetry the conformal compactification for hyperboloidal foliations with nonvanishing constant mean curvature. The conformal factor and the coordinates are chosen such that...

A template bank for gravitational waveforms from coalescing binary black holes: I. non-spinning binaries (2008)

Ajith, P., Babak, Stanislav, Chen, Yanbei, Hewitson, Martin, Krishnan, Badri, Sintes, A. M., ...

Gravitational waveforms from the inspiral and ring-down stages of the binary black hole coalescences can be modelled accurately by approximation/perturbation techniques in general relativity. Recent...

Implementation of standard testbeds for numerical relativity (2008)

Babiuc, Maria C., Husa, Sascha, Hinder, Ian, Lechner, Christiane, Schnetter, Erik, Szilagyi, Bela, ...

We discuss results that have been obtained from the implementation of the initial round of testbeds for numerical relativity which was proposed in the first paper of the Apples with Apples Alliance....

Template bank for gravitational waveforms from coalescing binary black holes: Nonspinning binaries (2008)

Ajith, P., Babak, Stanislav, Chen, Yanbei, Hewitson, Martin, Krishnan, Badri, Sintes, A. M., ...

Gravitational waveforms from the inspiral and ring-down stages of the binary black-hole coalescences can be modeled accurately by approximation/perturbation techniques in general relativity. Recent...

Comparison between numerical-relativity and post-Newtonian waveforms from spinning binaries: The orbital hang-up case (2008)

Hannam, Mark, Husa, Sascha, Brügmann, Bernd, Gopakumar, Achamveedu

We compare results from numerical simulations of spinning binaries in the “orbital hang-up” case, where the binary completes at least nine orbits before merger, with post-Newtonian results using...

Wormholes and trumpets: Schwarzschild spacetime for the moving-puncture generation (2008)

Hannam, Mark, Husa, Sascha, Ohme, Frank, Brügmann, Bernd, O'Murchadha, Niall

We expand upon our previous analysis of numerical moving-puncture simulations of the Schwarzschild spacetime. We present a derivation of the family of analytic stationary 1+log foliations of the...

Comparison between numerical relativity and a new class of post-Newtonian gravitational-wave phase evolutions: The nonspinning equal-mass case (2008)

Gopakumar, Achamveedu, Hannam, Mark, Husa, Sascha, Brügmann, Bernd

We compare the phase evolution of equal-mass nonspinning black-hole binaries from numerical relativity (NR) simulations with post-Newtonian (PN) results obtained from three PN approximants: the...

Final spin from the coalescence of two black holes (2008)

Rezzolla, Luciano, Barausse, Enrico, Dorband, Ernst Nils, Pollney, Denis, Reisswig, Christian, Seiler, Jennifer, ...

We provide a compact analytic formula to compute the spin of the black hole produced by the coalescence of two black holes following a quasicircular inspiral. Without additional fits than those...

Accurate effective-one-body waveforms of inspiralling and coalescing black-hole binaries (2008)

Damour, Thibault, Nagar, Alessandro, Hannam, Mark, Husa, Sascha, Brügmann, Bernd

The effective-one-body (EOB) formalism contains several flexibility parameters, notably a5, vpole, and [overline a]RR. We show here how to jointly constrain the values of these parameters by...

Resolving Super Massive Black Holes with LISA (2008)

Babak, Stanislav, Hannam, Mark, Husa, Sascha, Schutz, Bernard F.

We study the angular resolution of the gravitational wave detector LISA and show that numerical relativity can drastically improve the accuracy of position location for coalescing Super Massive Black...

Template bank for gravitational waveforms from coalescing binary black holes: Nonspinning binaries (2008)

Ajith, P., Babak, Stanislav, Chen, Yanbei, Hewitson, Martin, Krishnan, Badri, Sintes, A. M., ...

Gravitational waveforms from the inspiral and ring-down stages of the binary black-hole coalescences can be modeled accurately by approximation/perturbation techniques in general relativity. Recent...

Comparison between numerical relativity and a new class of post-Newtonian gravitational-wave phase evolutions: the non-spinning equal-mass case (2007)

Gopakumar, Achamveedu, Hannam, Mark, Husa, Sascha, Brügmann, Bernd

We compare the phase evolution of equal-mass nonspinning black-hole binaries from numerical relativity (NR) simulations with post-Newtonian (PN) results obtained from three PN approximants: the...

Comparison between numerical-relativity and post-Newtonian waveforms from spinning binaries: the orbital hang-up case (2007)

Hannam, Mark, Husa, Sascha, Brügmann, Bernd, Gopakumar, Achamveedu

We compare results from numerical simulations of spinning binaries in the "orbital hangup" case, where the binary completes at least nine orbits before merger, with post-Newtonian results using the...

On the final spin from the coalescence of two black holes (2007)

Rezzolla, Luciano, Barausse, Enrico, Dorband, Ernst Nils, Pollney, Denis, Reisswig, Christian, Seiler, Jennifer, ...

We provide a compact analytic formula to compute the spin of the black hole produced by the coalescence of two black holes. The expression, which uses an analytic fit of numerical-relativity data and...

Exploring black hole superkicks (2007)

Bruegmann, Bernd, Gonzalez, Jose, Hannam, Mark, Husa, Sascha, Sperhake, Ulrich

Recent calculations of the recoil velocity in black-hole binary mergers have found kick velocities of $\approx2500 $km/s for equal-mass binaries with anti-aligned initial spins in the orbital plane....

Where post-Newtonian and numerical-relativity waveforms meet (2007)

Hannam, Mark, Husa, Sascha, Gonzalez, Jose A., Sperhake, Ulrich, Bruegmann, Bernd

We analyze numerical-relativity (NR) waveforms that cover nine orbits (18 gravitational-wave cycles) before merger of an equal-mass system with low eccentricity, with numerical uncertainties of 0.25...

Reducing eccentricity in black-hole binary evolutions with initial parameters from post-Newtonian inspiral (2007)

Husa, Sascha, Hannam, Mark, Gonzalez, Jose A., Sperhake, Ulrich, Bruegmann, Bernd

Standard choices of quasi-circular orbit parameters for black-hole binary evolutions result in eccentric inspiral. We introduce a conceptually simple method, which is to integrate the post-Newtonian...

Reducing phase error in long numerical binary black hole evolutions with sixth order finite differencing (2007)

Husa, Sascha, Gonzalez, Jose A., Hannam, Mark, Bruegmann, Bernd, Sperhake, Ulrich

We describe a modification of a fourth-order accurate ``moving puncture'' evolution code, where by replacing spatial fourth-order accurate differencing operators in the bulk of the grid by a specific...

Head-On collisions of different initial data (2007)

Sperhake, Ulrich, Bruegmann, Bernd, Gonzalez, Jose, Hannam, Mark, Husa, Sascha

We discuss possible origins for discrepancies observed in the radiated energies in head-on collisions of non-spinning binaries starting from Brill-Lindquist and superposed Kerr-Schild data. For this...

Inspiral, merger and ringdown of unequal mass black hole binaries: a multipolar analysis (2007)

Berti, Emanuele, Cardoso, Vitor, Gonzalez, Jose A., Sperhake, Ulrich, Hannam, Mark, Husa, Sascha, ...

We study the inspiral, merger and ringdown of unequal mass black hole binaries by analyzing a catalogue of numerical simulations for seven different values of the mass ratio (from q=M2/M1=1 to q=4)....

Binary black holes on a budget: Simulations using workstations (2007)

Marronetti, Pedro, Tichy, Wolfgang, Bruegmann, Bernd, Gonzalez, Jose, Hannam, Mark, Husa, Sascha, ...

Binary black hole simulations have traditionally been computationally very expensive: current simulations are performed in supercomputers involving dozens if not hundreds of processors, thus...

A phenomenological template family for black-hole coalescence waveforms (2007)

Ajith, P., Babak, Stanislav, Chen, Yanbei, Hewitson, Martin, Krishnan, Badri, Whelan, J. T., ...

Recent progress in numerical relativity has enabled us to model the non-perturbative merger phase of the binary black-hole coalescence problem. Based on these results, we propose a phenomenological...

Geometry and Regularity of Moving Punctures (2007)

Hannam, Mark, Husa, Sascha, Pollney, Denis, Bruegmann, Bernd, O'Murchadha, Niall

The puncture method for black holes in numerical relativity has recently been extended to punctures that move across the grid, which has led to significant advances in numerical simulations of...

Hyperboloidal foliations with scri-fixing in spherical symmetry (2006)

Zenginoglu, Anil, Husa, Sascha

We study in spherical symmetry the conformal compactification for hyperboloidal foliations with nonvanishing constant mean curvature. The conformal factor and the coordinates are chosen such that...

Where do moving punctures go? (2006)

Hannam, Mark, Husa, Sascha, Murchadha, Niall Ó, Brügmann, Bernd, González, José A., Sperhake, Ulrich

Currently the most popular method to evolve black-hole binaries is the ``moving puncture'' method. It has recently been shown that when puncture initial data for a Schwarzschild black hole are...

Beyond the Bowen-York extrinsic curvature for spinning black holes (2006)

Hannam, Mark, Husa, Sascha, Bruegmann, Bernd, Gonzalez, Jose A., Sperhake, Ulrich

It is well-known that Bowen-York initial data contain spurious radiation. Although this ``junk'' radiation has been seen to be small for non-spinning black-hole binaries in circular orbit, its...

Total recoil: the maximum kick from nonspinning black-hole binary inspiral (2006)

Gonzalez, Jose A., Sperhake, Ulrich, Bruegmann, Bernd, Hannam, Mark, Husa, Sascha

When unequal-mass black holes merge, the final black hole receives a ``kick'' due to the asymmetric loss of linear momentum in the gravitational radiation emitted during the merger. The magnitude of...

Calibration of Moving Puncture Simulations (2006)

Bruegmann, Bernd, Gonzalez, Jose A., Hannam, Mark, Husa, Sascha, Sperhake, Ulrich, Tichy, Wolfgang

We present single and binary black hole simulations that follow the moving puncture paradigm of simulating black-hole spacetimes without excision, and use moving boxes mesh refinement. Focussing on...

Geometry and Regularity of Moving Punctures (2006)

Hannam, Mark, Husa, Sascha, Pollney, Denis, Bruegmann, Bernd, O'Murchadha, Niall

Significant advances in numerical simulations of black-hole binaries have recently been achieved using the puncture method. We examine how and why this method works by evolving a single black hole....

Kranc: a Mathematica application to generate numerical codes for tensorial evolution equations (2006)

Husa, Sascha, Hinder, Ian, Lechner, Christiane

We present a suite of Mathematica-based computer-algebra packages, termed "Kranc", which comprise a toolbox to convert (tensorial) systems of partial differential evolution equations to parallelized...

Numerical stability for finite difference approximations of Einstein's equations (2006)

Calabrese, Gioel, Hinder, Ian, Husa, Sascha

We extend the notion of numerical stability of finite difference approximations to include hyperbolic systems that are first order in time and second order in space, such as those that appear in...

Hyperboloidal data and evolution (2006)

Husa, Sascha, Schneemann, Carsten, Vogel, Tilman, Zenginoglu, Anil

We discuss the hyperboloidal evolution problem in general relativity from a numerical perspective, and present some new results. Families of initial data which are the hyperboloidal analogue of Brill...

Hyperboloidal data and evolution (2005)

Husa, Sascha, Schneemann, Carsten, Vogel, Tilman, Zenginoglu, Anil

We discuss the hyperboloidal evolution problem in general relativity from a numerical perspective, and present some new results. Families of initial data which are the hyperboloidal analogue of Brill...

Numerical stability for finite difference approximations of Einstein's equations (2005)

Calabrese, Gioel, Hinder, Ian, Husa, Sascha

We extend the notion of numerical stability of finite difference approximations to include hyperbolic systems that are first order in time and second order in space, such as those that appear in...

News from critical collapse: Bondi mass, tails, and quasi-normal modes (2005)

Aichelburg,P. C., Husa,Sascha, Pürrer,M.

We discuss critical gravitational collapse on the threshold of apparent horizon formation as a model both for the discussion of global aspects of critical collapse and for numerical studies in a...

News from critical collapse: Bondi mass, tails, and quasi-normal modes (2005)

Aichelburg, Peter C., Husa, Sascha, Pürrer, Michael

We discuss critical gravitational collapse on the threshold of apparent horizon formation as a model both for the discussion of global aspects of critical collapse and for numerical studies in a...

From Tensor Equations to Numerical Code -- Computer Algebra Tools for Numerical Relativity (2004)

Lechner, Christiane, Alic, Dana, Husa, Sascha

In this paper we present our recent work in developing a computer-algebra tool for systems of partial differential equations (PDEs), termed "Kranc". Our work is motivated by the problem of finding...

News from Critical Collapse: Bondi Mass, Tails and Quasinormal Modes (2004)

Pürrer, Michael, Husa, Sascha, Aichelburg, Peter C.

We discuss critical gravitational collapse on the threshold of apparent horizon formation as a model both for the discussion of global aspects of critical collapse and for numerical studies in a...

Kranc: a Mathematica application to generate numerical codes for tensorial evolution equations (2004)

Husa, Sascha, Hinder, Ian, Lechner, Christiane

We present a suite of Mathematica-based computer-algebra packages, termed "Kranc", which comprise a toolbox to convert (tensorial) systems of partial differential evolution equations to parallelized...

Towards standard testbeds for numerical relativity (2004)

Alcubierre, Miguel, Allen, Gabrielle, Bona, Carles, Fiske, David, Goodale, Tom, Guzmán, F. Siddhartha, ...

In recent years, many different numerical evolution schemes for Einstein's equations have been proposed to address stability and accuracy problems that have plagued the numerical relativity community...

Toward standard testbeds for numerical relativity (2004)

Alcubierre,Miguel, Allen,Gabrielle, Bona,Carles, Fiske,David, Goodale,Tom, Guzman,F. Siddhartha, ...

In recent years, many different numerical evolution schemes for Einstein's equations have been proposed to address stability and accuracy problems that have plagued the numerical relativity community...

Toward standard testbeds for numerical relativity (2004)

Alcubierre, Miguel, Allen, Gabrielle, Bona, Carles, Fiske, David R., Goodale, Tom, Guzman, F. Siddhartha, ...

In recent years, many different numerical evolution schemes for Einstein's equations have been proposed to address stability and accuracy problems that have plagued the numerical relativity community...

Mode coupling in the nonlinear response of black holes (2003)

Zlochower, Yosef, Gomez, Roberto, Husa, Sascha, Lehner, Luis, Winicour, Jeffrey

We study the properties of the outgoing gravitational wave produced when a non-spinning black hole is excited by an ingoing gravitational wave. Simulations using a numerical code for solving...

Toward standard testbeds for numerical relativity (2003)

Alcubierre, Miguel, Allen, Gabrielle, Bona, Carles, Fiske, David, Goodale, Tom, Guzman, F. Siddharta, ...

In recent years, many different numerical evolution schemes for Einstein's equations have been proposed to address stability and accuracy problems that have plagued the numerical relativity community...

Computer Algebra Applications for Numerical Relativity (2003)

Husa, Sascha, Lechner, Christiane

We discuss the application of computer algebra to problems commonly arising in numerical relativity, such as the derivation of 3+1-splits, manipulation of evolution equations and automatic code...

A numerical relativistic model of a massive particle in orbit near a Schwarzschild black hole (2003)

Bishop, Nigel T., Gomez, Roberto, Husa, Sascha, Lehner, Luis, Winicour, Jeffrey

We present a method for computing the evolution of a spacetime containing a massive particle and a black hole. The essential idea is that the gravitational field is evolved using full numerical...

Mode coupling in the nonlinear response of black holes (2003)

Zlochower,Yosef, Gomez,Roberto, Husa,Sascha, Lehner,Luis, Winicour,Jeffrey

We model the nonlinear generation of waveforms from an excited non-spinning black hole. The results exhibit several important features. When compared to the results obtained by a linearized...

A numerical relativistic model of a massive particle in orbit near a Schwarzschild black hole (2003)

Bishop,Nigel T., Gomez,Roberto, Husa,Sascha, Lehner,Luis

We present a method for computing the evolution of a spacetime containing a massive particle and a black hole. The essential idea is that the gravitational field is evolved using full numerical...

Numerical relativity with the conformal field equations (2003)

Husa, Sascha

I discuss the conformal approach to the numerical simulation of radiating isolated systems in general relativity. The method is based on conformal compactification and a reformulation of the Einstein...

Mode coupling in the nonlinear response of black holes (2003)

Zlochower, Yosef, Gomez, Roberto, Husa, Sascha, Lehner, Luis, Winicour, Jeffrey

We model the nonlinear generation of waveforms from an excited non-spinning black hole. The results exhibit several important features. When compared to the results obtained by a linearized...

A numerical relativistic model of a massive particle in orbit near a Schwarzschild black hole (2003)

Bishop, Nigel T., Gomez, Roberto, Husa, Sascha, Lehner, Luis

We present a method for computing the evolution of a spacetime containing a massive particle and a black hole. The essential idea is that the gravitational field is evolved using full numerical...

Gravitational Waves from a Fissioning White Hole (2002)

Gomez, Roberto, Husa, Sascha, Lehner, Luis, Winicour, Jeffrey

We present a fully nonlinear calculation of the waveform of the gravitational radiation emitted in the fission of a vacuum white hole. At early times, the waveforms agree with close-approximation...

Numerical relativity with the conformal field equations (2002)

Husa, Sascha

I discuss the conformal approach to the numerical simulation of radiating isolated systems in general relativity. The method is based on conformal compactification and a reformulation of the Einstein...

Problems and Successes in the Numerical Approach to the Conformal Field Equations (2002)

Husa, Sascha

This talk reports on the status of an approach to the numerical study of isolated systems with the conformal field equations. We first describe the algorithms used in a code which has been developed...

A new transition between discrete and continuous self-similarity in critical gravitational collapse (2002)

Lechner, Christiane, Thornburg, Jonathan, Husa, Sascha, Aichelburg, Peter C.

We analyze a bifurcation phenomenon associated with critical gravitational collapse in a family of self-gravitating SU(2) σ models. As the dimensionless coupling constant decreases, the critical...

A New Tradition between Discrete and Contiuous Self-Similarity in Critical Gravitational Collapse (2002)

Lechner,Christiane, Thornburg,Jonathan, Husa,Sascha, Aichelburg,Peter C.

We analyze a bifurcation phenomenon associated with critical gravitational collapse in a family of self-gravitating SU(2) sigma models. As the dimensionless coupling constant decreases, the critical...

Retarded radiation from colliding black holes in the close limit (2002)

Husa,Sascha, Zlochower,Yosef, Gomez,Roberto, Winicour,Jeffrey

We use null hypersurface techniques in a new approach to calculate the retarded waveform from a binary black hole merger in the close approximation. The process of removing ingoing radiation from the...

Gravitational waves from a fissioning white hole (2002)

Gómez,Roberto, Husa,Sascha, Lehner,Luis, Winicour,Jeffrey

We present a fully nonlinear calculation of the waveform of the gravitational radiation emitted in the fission of a vacuum white hole. At early times, the waveforms agree with close approximation...

A New Tradition between Discrete and Contiuous Self-Similarity in Critical Gravitational Collapse (2002)

Lechner, Christiane, Thornburg, Jonathan, Husa, Sascha, Aichelburg, Peter C.

We analyze a bifurcation phenomenon associated with critical gravitational collapse in a family of self-gravitating SU(2) sigma models. As the dimensionless coupling constant decreases, the critical...

Retarded radiation from colliding black holes in the close limit (2002)

Husa, Sascha, Zlochower, Yosef, Gomez, Roberto, Winicour, Jeffrey

We use null hypersurface techniques in a new approach to calculate the retarded waveform from a binary black hole merger in the close approximation. The process of removing ingoing radiation from the...

Problems and Successes in the Numerical Approach to theConformal Field Equations (2002)

Husa, Sascha

This talk reports on the status of an approach to the numerical study of isolated systems with the conformal field equations. We first describe the algorithms used in a code which has been developed...

Gravitational waves from a fissioning white hole (2002)

Gomez, Roberto, Husa, Sascha, Lehner, Luis, Winicour, Jeffrey

We present a fully nonlinear calculation of the waveform of the gravitational radiation emitted in the fission of a vacuum white hole. At early times, the waveforms agree with close approximation...

A New Transition between Discrete and Continuous Self-Similarity in Critical Gravitational Collapse (2001)

Lechner, Christiane, Thornburg, Jonathan, Husa, Sascha, Aichelburg, Peter C.

We analyze a bifurcation phenomenon associated with critical gravitational collapse in a family of self-gravitating SU(2) $\sigma$-models. As the dimensionless coupling constant decreases, the...

Semiglobal Numerical Calculations of Asymptotically Minkowski Spacetimes (2001)

Husa, Sascha

This talk reports on recent progress toward the semiglobal study of asymptotically flat spacetimes within numerical relativity. The development of a 3D solver for asymptotically Minkowski-like...

Retarded radiation from colliding black holes in the close limit (2001)

Husa, Sascha, Zlochower, Yosef, Gomez, Roberto, Winicour, Jeffrey

We use null hypersurface techniques in a new approach to calculate the retarded waveform from a binary black hole merger in the close approximation. The process of removing ingoing radiation from the...

The close limit from a null point of view: The advanced solution (2001)

Campanelli,Manuela, Gomez,Roberto, Husa,Sascha, Winicour,Jeffrey, Zlochower,Yosef

We present a characteristic algorithm for computing the perturbation of a Schwarzschild spacetime by means of solving the Teukolsky equation. We implement the algorithm as a characteristic evolution...

Complete null data for a black hole collision (2001)

Husa, Sascha, Gomez, Roberto, Winicour, Jeffrey

We discuss a sequence of numerically constructed geometries describing binary black hole event horizons -- providing the necessary input for characteristic evolution of the exterior spacetime. Our...

Complete null data for a black hole collision (2001)

Husa,Sascha, Gomez,Roberto, Winicour,Jeffrey

We discuss a sequence of numerically constructed geometries describing binary black hole event horizons -- providing the necessary input for characteristic evolution of the exterior spacetime. Our...

Colliding black holes from a null point of view: the close limit (2001)

Husa,Sascha, Campanelli,Manuela, Gomez,Roberto, Winicour,Jeffrey, Zlochower,Yosef

We present a characteristic algorithm for computing the perturbations of a Schwarzschild spacetime by means of solving the Teukolsky equations. Our methods and results are expected to have direct...

Complete null data for a black hole collision (2001)

Husa, Sascha, Gomez, Roberto, Winicour, Jeffrey

We discuss a sequence of numerically constructed geometries describing binary black hole event horizons -- providing the necessary input for characteristic evolution of the exterior spacetime. Our...

Colliding black holes from a null point of view: the close limit (2001)

Husa, Sascha, Campanelli, Manuela, Gomez, Roberto, Winicour, Jeffrey, Zlochower, Yosef

We present a characteristic algorithm for computing the perturbations of a Schwarzschild spacetime by means of solving the Teukolsky equations. Our methods and results are expected to have direct...

The close limit from a null point of view: The advanced solution (2001)

Campanelli, Manuela, Gomez, Roberto, Husa, Sascha, Winicour, Jeffrey, Zlochower, Yosef

We present a characteristic algorithm for computing the perturbation of a Schwarzschild spacetime by means of solving the Teukolsky equation. We implement the algorithm as a characteristic evolution...

Semiglobal Numerical Calculations of Asymptotically Minkowski Spacetimes (2001)

Husa, Sascha

This talk reports on recent progress toward the semiglobal study of asymptotically flat spacetimes within numerical relativity. The development of a 3D solver for asymptotically Minkowski-like...

Colliding black holes from a null point of view: the close limit (2000)

Husa, Sascha, Campanelli, Manuela, Gomez, Roberto, Winicour, Jeffrey, Zlochower, Yosef

We present a characteristic algorithm for computing the perturbations of a Schwarzschild spacetime by means of solving the Teukolsky equations. Our methods and results are expected to have direct...

The close limit from a null point of view: the advanced solution (2000)

Campanelli, Manuela, Gomez, Roberto, Husa, Sascha, Winicour, Jeffrey, Zlochower, Yosef

We present a characteristic algorithm for computing the perturbation of a Schwarzschild spacetime by means of solving the Teukolsky equation. We implement the algorithm as a characteristic evolution...

Complete null data for a black hole collision (2000)

Gomez, Roberto, Husa, Sascha, Winicour, Jeffrey

We present an algorithm for calculating the complete data on an event horizon which constitute the necessary input for characteristic evolution of the exterior spacetime. We apply this algorithm to...

Type II Critical Collapse of a Self-Gravitating Nonlinear $\sigma$-Model (2000)

Husa, Sascha, Lechner, Christiane, Pürrer, Michael, Thornburg, Jonathan, Aichelburg, Peter C.

We report on the existence and phenomenology of type II critical collapse within the one-parameter family of SU(2) $\sigma$-models coupled to gravity. Numerical investigations in spherical symmetry...

SU(2) Cosmological Solitons (2000)

Lechner, Christiane, Husa, Sascha, Aichelburg, Peter C.

We present a class of numerical solutions to the SU(2) nonlinear $\sigma$-model coupled to the Einstein equations with cosmological constant $\Lambda\geq 0$ in spherical symmetry. These solutions are...

Type II Critical Collapse of a Self-Gravitating Nonlinear Sigma Model (2000)

Husa,Sascha, Lechner,Christiane, Pürrer,Michael, Thornburg,Jonathan, Aichelburg,Peter C.

We report on the existence and phenomenology of type II critical collapse within the one-parameter family of SU(2) sigma models coupled to gravity. Numerical investigations in spherical symmetry show...

Type II Critical Collapse of a Self-Gravitating Nonlinear Sigma Model (2000)

Husa, Sascha, Lechner, Christiane, Pürrer, Michael, Thornburg, Jonathan, Aichelburg, Peter C.

We report on the existence and phenomenology of type II critical collapse within the one-parameter family of SU(2) sigma models coupled to gravity. Numerical investigations in spherical symmetry show...

The Asymmetric Merger of Black Holes (1999)

Husa, Sascha, Winicour, Jeffrey

We study event horizons of non-axisymmetric black holes and show how features found in axisymmetric studies of colliding black holes and of toroidal black holes are non-generic and how new features...

Asymptotically Flat Initial Data for Gravitational Wave Spacetimes, Conformal Compactification and Conformal Symmetry (1998)

Husa, Sascha

We study the utilization of conformal compactification within the conformal approach to solving the constraints of general relativity for asymptotically flat initial data. After a general discussion...

Initial Data for General Relativity Containing a Marginally Outer Trapped Torus (1996)

Husa, Sascha

Asymptotically flat, time-symmetric, axially symmetric and conformally flat initial data for vacuum general relativity are studied numerically on $R^3$ with the interior of a standard torus cut out....

Initial Data for General Relativity with Toroidal Conformal Symmetry (1994)

Beig, Robert, Husa, Sascha

A new class of time-symmetric solutions to the initial value constraints of vacuum General Relativity is introduced. These data are globally regular, asymptotically flat (with possibly several...

Computer Algebra Applications for Numerical Relativity

Husa,Sascha, Lechner,Christiane

We discuss the application of computer algebra to problems commonly arising in numerical relativity, such as the derivation of 3+1-splits, manipulation of evolution equations and automatic code...

Kranc: a Mathematica application to generate numerical codes for tensorial evolution equations

Husa,Sascha, Hinder,Ian, Lechner,Christiane

We present a suite of Mathematica-based computer-algebra packages, termed "Kranc", which comprise a toolbox to convert (tensorial) systems of partial differential evolution equations to parallelized...

Computer Algebra Applications for Numerical Relativity

Husa, Sascha, Lechner, Christiane

We discuss the application of computer algebra to problems commonly arising in numerical relativity, such as the derivation of 3+1-splits, manipulation of evolution equations and automatic code...

From Tensor Equations to Numerical Code -- Computer Algebra Tools for Numerical Relativity

Lechner, Christiane, Alic, D., Husa, Sascha

In this paper we present our recent work in developing a computer-algebra tool for systems of partial differential equations (PDEs), termed "Kranc". Our work is motivated by the problem of finding...

Gravitational-wave detectability of equal-mass black-hole binaries with aligned spins

Reisswig, Christian, Husa, Sascha, Rezzolla, Luciano, Dorband, Ernst Nils, Pollney, Denis, Seiler, Jennifer

Binary black-hole systems with spins aligned or anti-aligned to the orbital angular momentum provide the natural ground to start detailed studies of the influence of strong-field spin effects on...