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Preprints by folks in Pittsburgh (CMU, Pitt, Duquesne) listed by year, most recent first.

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2005

• The 3-dimensional Einstein-Klein-Gordon system in characteristic numerical relativity
  W. Barreto, A. Da Silva, R. Gómez, L. Lehner, L. Rosales, and J. Winicour
  Phys. Rev. D 71, 064028 (2005), gr-qc/0412066
  
  
• On characteristic initial data for a star orbiting a black hole
  Nigel T. Bishop, Roberto Gómez, Luis Lehner, Manoj Marahaj, and J. Winicour
  Phys. Rev. D 72, 024002 (2005), gr-qc/0412080
  
  Modeling the Black Hole Excision Problem
  B. Szilagyi, H.O. Kreiss, and J. Winicour
  Phys. Rev. D 71, 104035 (2005), gr-qc/0412101
• Well-posed first order reduction of the characteristic problem of the linearized Einstein equations
  Simonetta Frittelli
  Phys. Rev. D 71, 024021 (2005), gr-qc/0408035

2004

• Estimates for first-order homogeneous linear characteristic problems
  Simonetta Frittelli
  To appear in J. Phys. A (April 2005), math-ph/0408010
• Estimates for the characteristic problem of the first-order reduction of the wave equation
  Simonetta Frittelli
  J. Phys. A: Math. Gen. 37 (2004) 8639-8655, math-ph/0408007
• Some mathematical problems in numerical relativity
  Maria Babiuc, Bela Szilagyi, Jeffrey Winicour, gr-qc/0404092
• Cartan Normal Conformal Connections from Pairs of 2nd Order PDE's
  Emanuel Gallo, Carlos Kozameh, Ezra T. Newman, Kiplin Perkins
  Class. Quantum Grav. 21 4063-4086 (2004), gr-qc/0404072
• Potential for ill-posedness in several 2^nd-order formulations of the Einstein equations
  Simonetta Frittelli
  Phys. Rev. D 70, 044029 (2004), gr-qc/0404071
• Einstein boundary conditions for the Einstein equations in the conformal-traceless decomposition
  Simonetta Frittelli and Roberto Gomez
  Phys. Rev. D 70, 064008 (2004), gr-qc/0404070
• Maxwell Fields and Shear-Free Null Geodesic Congruences
  Ezra Newman
  Class. Quantum Grav. 21 3197-3221 (2004), gr-qc/0402056
• Aberration by gravitational lenses in motions
  Simonetta Frittelli
  Mon. Not. Roy. Astron. Soc., 344 L85-L87 (2003), astro-ph/0311189
• On bending angles by gravitational lenses in motions
  Simonetta Frittelli
  Mon. Not. Roy. Astron. Soc., 340 457-462 (2003), astro-ph/0212207
• Einstein boundary conditions in relation to constraint propagation for the initial-boundary value problem of the Einstein equations
  Simonetta Frittelli and Roberto Gómez
  Phys. Rev. D 69, 124020 (2004), gr-qc/0310064

2003

• A numerical relativistic model of a massive particle in orbit near a Schwarzschild black hole
  Nigel T. Bishop, Roberto Gómez, Sascha Husa, Luis Lehner, and Jeffrey Winicour
  Phys. Rev. D 68, 084015 (2003), gr-qc/0301060
• Mode coupling in the nonlinear response of black holes
  Yosef Zlochower, Roberto Gómez, Sascha Husa, Luis Lehner, Jeffrey Winicour
  Phys. Rev. D 68, 084014 (2003),  gr-qc/0306098
• First-order quasilinear canonical representation of the characteristic formulation of the Einstein equations
  Roberto Gómez and Simonetta Frittelli
  Phys. Rev. D 68, 084013 (2003), gr-qc/0303104
• Einstein boundary conditions for the 3+1 Einstein equations
  Simonetta Frittelli and Roberto Gómez
  Phys. Rev. D 68, 044014 (2003), gr-qc/0302071
• Well-Posed Initial-Boundary Evolution in General Relativity
  Bela Szilagyi and Jeffrey Winicour.
  Phys. Rev. D 68 , 041501 (2003), gr-qc/0205044
• Boundary conditions for hyperbolic formulations of the Einstein equations
  Simonetta Frittelli and Roberto Gómez
  Class. Quantum Grav., 20 (11) 2379-2392, (2003), gr-qc/0302032
• Toward standard testbeds for numerical relativity
  Miguel Alcubierre, Gabrielle Allen, Carles Bona, David Fiske, Tom Goodale, 
  F. Siddharta Guzman, Ian Hawke, Scott H. Hawley, Sascha Husa, Michael Koppitz, 
  Christiane Lechner, Denis Pollney, David Rideout, Marcelo Salgado, Erik Schnetter, 
  Edward Seidel, Hisa-aki Shinkai, Bela Szilagyi, Deirdre Shoemaker, Ryoji Takahashi, 
  Jeffrey Winicour,
  Class.Quant.Grav. 21, 589 (2004), gr-qc/0305023
• Conformal Einstein equations and Cartan conformal connection
  Carlos Kozameh, Ezra T Newman, Pawel Nurowski
  Class. Quantum Grav., 20 3029-3036, (2003),  gr-qc/0302080
• Projective connections associated with second order ODEs
  Ezra T Newman, Pawel Nurowski
  Class. Quantum Grav., 20 2325-2336, (2003),  gr-qc/0302016

2002

• Gravitational waveforms from a fissioning white hole
  Roberto Gómez, Sascha Husa, and Jeffrey Winicour
  Phys. Rev. D 66, 064019 (2002), gr-qc/0205038.
• Retarded radiation from colliding black holes in the close limit
  Sascha Husa, Yosef Zlochower, Roberto Gómez, and Jeffrey Winicour
  Phys.Rev. D 65, 084034 (2002), gr-qc/0108075.
• Wavefronts, Caustic Sheets, and Caustic Surfing in Gravitational Lensing
  S. Frittelli and  A.O. Petters
  J.Math.Phys. 43, 5578-5611  (2002), astro-ph/0208135
• Dynamics of Fermat potentials in non-perturbative gravitational lensing
  Simonetta Frittelli and Ezra T. Newman
  Phys. Rev. D 65, 123006 (2002), gr-qc/0205016.
• Fermat Potentials for Non-Perturbative Gravitational Lensing
  Simonetta Frittelli, Thomas P. Kling, and Ezra T. Newman
  Phys. Rev. D 65, 123007 (2002), gr-qc/0205014.
• Image distortion by thick lenses
  Simonetta Frittelli and Thomas E. Oberst
  Phys. Rev. D 65, 023005 (2002).
• On a Classical, Geometric Origin of Magnetic Moments, Spin-Angular Momentum and the Dirac Gyromagnetic Ratio
  Ezra T. Newman
  Phys. Rev. D 65, 104005 (2002), gr-qc/0201055.

2001

• Boundary conditions in linearized harmonic gravity
  Bela Szilagyi, Bernd Schmidt, Jeffrey Winicour
  Phys.Rev. D 65, 064015 (2002), gr-qc/0106026.
• Gravitational waveforms with controlled accuracy
  Roberto Gómez
  Phys. Rev. D 64, 024007 (2001), gr-qc/0103011
• Differential Geometry from Differential Equations
  Simonetta Frittelli, Carlos Kozameh and Ezra T. Newman
  Commun. Math. Phys. 223 383-408 (2001), gr-qc/0012058
• Image distortion from optical scalars in non perturbative gravitational lensing
  Simonetta Frittelli, Thomas P. Kling and Ezra T. Newman
  Phys.Rev. D 63 (2001) 023007, gr-qc/0011108
• Image distortion in non perturbative gravitational lensing
  Simonetta Frittelli, Thomas P. Kling and Ezra T. Newman
  Phys. Rev. D 63 (2001) 023006, gr-qc/0011107.
• The close limit from a null point of view: the advanced solution
  Manuela Campanelli, Roberto Gómez, Sascha Husa, Jeffrey Winicour, Yosef Zlochower
  Phys. Rev. D 63 (2001), 124013, gr-qc/0012107
• Complete null data for a black hole collision
  Roberto Gómez, Sascha Husa, and Jeffrey Winicour
  Phys. Rev. D 64, 024010 (2001), gr-qc/0009092

2000

• Colliding black holes from a null point of view: the close limit
  Sascha Husa, Manuela Campanelli, Roberto Gómez, Jeffrey Winicour, and Yosef Zlochower
  Contribution to the 9th Marcel Grossmann meeting (MG9), Rome, July 2000, gr-qc/0012110.
• Grazing Collisions of Black Holes via the Excision of Singularities
  Steve Brandt, Randall Correll, Roberto Gómez, Mijan Huq, Pablo Laguna, Luis Lehner, Pedro Marronetti, Richard A. Matzner, David Neilsen, Jorge Pullin, Erik Schnetter, Deirdre Shoemaker, Jeffrey Winicour
  Phys. Rev. Lett. 85 5496--5499, (2000), gr-qc/0009047.
• Comparative Studies of Lensing Methods
  Thomas P. Kling, Ezra T. Newman, and Alejandro Perez
  Phys. Rev. D 62, 024025 (2000), gr-qc/0003057
• Iterative Approach to Gravitational Lensing Theory
  Thomas P. Kling, Ezra T. Newman, and Alejandro Perez
  Phys. Rev. D 61, 104007 (2000), gr-qc/9908082
• Cauchy boundaries in linearized gravitational theory
  Bela Szilagyi, Nigel T. Bishop, Roberto Gómez, and Jeffrey Winicour
  Phys. Rev. D 62, 104006 (2000), gr-qc/9912030.
• Spacetime perspective of Schwarzschild lensing
  Simonetta Frittelli, Thomas P. Kling, and Ezra T. Newman
  Phys. Rev. D 61, 064021, (2000), gr-qc/0006082
• The Theory of Caustics and Wavefront Singularities with Physical Applications
  Juergen Ehlers and Ezra T. Newman
  J. Math. Phys. 41, 3344-3378 (2000), gr-qc/9906065
• Ill-posedness in the Einstein equations
  Simonetta Frittelli and Roberto Gómez
  J. Math. Phys. 41, 5535-5549, (2000), gr-qc/0006082
• A New Way to Make Waves
  Jeffrey Winicour
  In Proceeding of CIMENICS 2000, The Vth International Congress on Numerical Methods in Engineering and Applied Science (Puerto La Cruz, Venezuela, March 2000), gr-qc/0003029

1999

• Well-posed forms of the 3+1 conformally-decomposed Einstein equations.
  Simonetta Frittelli and Oscar A. Reula
  J. Math. Phys. 40, 5143 (1999), gr-qc/9904048
• The Characteristic Treatment of Black Holes
  Jeffrey Winicour
  Prog. of Theor. Phys. Suppl. 136, 57 (1999)
  Proceedings of the Yukawa International Seminar, Kyoto, Japan, June 1999
• The Eikonal equation in asymptotically flat space-times
  Simonetta Frittelli, Ezra. T. Newman, and Gilberto Silva-Ortigoza
  J. Math. Phys. 40, 1041 (1999)
• The Asymmetric Merger of Black Holes
  Sascha Husa and Jeffrey Winicour
  Phys. Rev. D 60 (1999) 084019, gr-qc/9905039
• Exact Solutions for the Intrinsic Geometry of Black Hole Coalescence.
  Luis Lehner, Nigel T. Bishop, Roberto Gómez, Bela Szilagyi, and Jeffrey Winicour
  Phys. Rev. D 60 (1999) 044005, gr-qc/9809034
• Incorporation of matter into characteristic numerical relativity.
  Nigel T. Bishop, Roberto Gómez, Luis Lehner, Manoj Maharaj, and Jeffrey Winicour
  Phys. Rev. D 60 (1999) 024005, gr-qc/9901056
• A Dissipative Algorithm for Wave-like Equations in the Characteristic Formulation.
  Luis Lehner
  J. Comp. Phys. 149, 59 (1999), gr-qc/9811095
• Characteristic Surface Data for the Eikonal Equation
  Ezra T. Newman and Alejandro Perez
  J. Math. Phys. 40, 1093-1102 (1999), gr-qc/9809016
• Einstein's Equations with Asymptotically Stable Constraint Propagation
  Othmar Brodbeck, Simonetta Frittelli, Peter Huebner, Oscar A. Reula
  J. Math. Phys. 40, 909 (1999), gr-qc/9809023
• Null Cones in Schwarzschild Geometry
  Thomas P. Kling and Ezra T. Newman
  Phys. Rev. D 59, 124002 (1999), gr-qc/9809037
• Existence and uniqueness of solutions to characteristic evolution in Bondi-Sachs coordinates in general relativity.
  Simonetta Frittelli and Luis Lehner
  Phys. Rev. D 59, 084012 (1999)
• The Eikonal Equation in Flat Space: Null Surfaces and Their Singularities I
  S. Frittelli, E.T. Newman, G. Silva-Ortigoza
  J. Math. Phys. 40, 383 (1999), gr-qc/9809019

1998

• A variational principle for time of arrival of null geodesics
  Simonetta Frittelli and Ezra T. Newman
  Contribution to J. Narlikar's festshcrift, gr-qc/9810067
• An Exact Universal Gravitational Lensing Equation
  Simonetta Frittelli and Ezra T. Newman
  Phys. Rev. D 59, 124001 (1999), gr-qc/9810017
• Black Hole data via a Kerr-Schild approach
  Nigel T. Bishop, Richard Isaacson, Manoj Maharaj, and Jeffrey Winicour
  Phys. Rev. D 57, 6113 (1998), gr-qc/9711076
• Asymptotically Flat Initial Data for Gravitational Wave Spacetimes, Conformal Compactification and Conformal Symmetry
  Sascha Husa
  Contribution to the 8th Conference on Theoretical Physics General Relativity and Gravitation in Bistrita-Nasaud, Romania, gr-qc/9811005.
• Characteristic Evolution and Matching
  J. Winicour
  Living Reviews, Volume 1 (1998), gr-qc/0102085
  
  
• Cauchy-characteristic matching.
  N. T. Bishop, R. Isaacson, R. Gómez, L. Lehner, B. Szilagyi, J. Winicour
  In Black Holes, Gravitational Radiation and the Universe, Eds. Bala R. Iyer and Biplab Bhawal, Kluwer Academic Publishers, P. O. Box 17, NL-3300 AA Dordrecht, The Netherlands, (1998), gr-qc/9801070.
• Stable characteristic evolution of generic 3-dimensional single-black-hole spacetimes.
  The Binary Black Hole Grand Challenge Alliance:
  Gómez, R.; Lehner L.; Marsa, R.; Winicour, J.;
  Abrahams, A.; Anderson, A; Anninos, P.; Baumgarte T.; Bishop, N.; Brandt S.; Browne, J.; Camarda, K.; Choptuik, M.; Correl, R.; Cook, G.; Evans, C.; Finn, L.; Fox, G.; Haupt, T.; Huq, M.; Kidder, L.; Klasky, S.; Laguna, P.; Landry, W.; Lenaghan, J.; Masso, J.; Matzner, R.A.; Mitra, S.; Papadopoulos, P.; Parashar, M.; Rezzolla, L.; Rupright, M.; Saied, F.; Saylor, P.; Scheel, M.; Seidel, E.; Shapiro, S.; Shoemaker, D.; Smarr, L.; Szilagyi, B.; Teukolsky, A.; van Putten, M.H.P.M.; Walker, P.; York, J.W
  Phys. Rev. Lett. 80, 3915-3918 (1998) , gr-qc/9801069
• Boosted three-dimensional black-hole evolutions with singularity excision.
  The Binary Black Hole Grand Challenge Alliance:
  G. B. Cook, M. F. Huq, S. A. Klasky, M. A. Scheel,
  A. M. Abrahams, A. Anderson, P. Anninos, T. W. Baumgarte, N. T. Bishop, S. R. Brandt, J. C. Browne, K. Camarda, M. W. Choptuik, C. R. Evans, L. S. Finn, G. C. Fox, R. Gómez, T. Haupt, L. E. Kidder, P. Laguna, W. Landry, L. Lehner, J. Lenaghan, R. L. Marsa, J. Masso, R. A. Matzner, S. Mitra, P. Papadopoulos, M. Parashar, L. Rezzolla, M. E. Rupright, F. Saied, P. E. Saylor, E. Seidel, S. L. Shapiro, D. Shoemaker, L. Smarr, W. M. Suen, B. Szilagyi, S. A. Teukolsky, M. H.P.M. van Putten, P. Walker, J. Winicour, J. W. York Jr.
  Phys. Rev. Lett. 80, 2512-2516 (1998), gr-qc/9711078
• Moving Black Holes in 3D
  R. Gómez, L. Lehner, R.L. Marsa, J. Winicour
  Phys. Rev. D 57, 4778-4788 (1998), gr-qc/9710138
• Gravitational wave extraction and outer boundary conditions by perturbative matching
  The Binary Black Hole Grand Challenge Alliance:
  A. M. Abrahams, L. Rezzolla, M. E. Rupright, A. Anderson, P. Anninos, T. W. Baumgarte, N. T. Bishop, S. R. Brandt, J. C. Browne, K. Camarda, M. W. Choptuik, G. B. Cook, C. R. Evans, L. S. Finn, G. Fox, R. Gómez, T. Haupt, M. F. Huq, L. E. Kidder, S. Klasky, P. Laguna, W. Landry, L. Lehner, J. Lenaghan, R. L. Marsa, J. Masso, R. A. Matzner, S. Mitra, P. Papadopoulos, M. Parashar, F. Saied, P. E. Saylor, M. A. Scheel, E. Seidel, S. L. Shapiro, D. Shoemaker, L. Smarr, B. Szilagyi, S. A. Teukolsky, M. H. P. M. van Putten, P. Walker, J. Winicour, J. W. York Jr
  Phys. Rev. Lett. 80, 1812-1815 (1998) , gr-qc/9709082

1997

• Singularities of wavefronts and lightcones in the context of GR via null foliations
  Simonetta Frittelli, Ezra T. Newman
  Twistor Newslett. 43, 14-21 (1997), gr-qc/0006077
• Black hole excision with matching
  R. Gómez, R. L. Marsa, J. Winicour
  Phys. Rev. D 56, 6310-6319 (1997), gr-qc/9708002
• High-powered Gravitational News
  Nigel T. Bishop, Roberto Gómez, Luis Lehner, Manoj Maharaj, Jeffrey Winicour
  Phys. Rev. D 56, 6298-6309 (1997), gr-qc/9708065
• Dynamics of light cone cuts of null infinity
  Simonetta Frittelli, Carlos N. Kozameh, Ezra T. Newman
  Phys. Rev. D 56, 4729  (1997)
• Quantization of the null-surface formulation of general relativity
  Simonetta Frittelli, Carlos N. Kozameh, Ezra T. Newman, Carlo Rovelli, Ranjeet S. Tate
  Phys. Rev. D 56, 889-907 (1997), gr-qc/9612010
• Note on the propagation of the constraints in standard 3+1 general relativity
  Simonetta Frittelli
  Phys. Rev. D 55, 5992 (1997)
• Pseudo-Minkowskian coordinates in asymptotically flat space-times
  Simonetta Frittelli, Ezra T. Newman
  Phys. Rev. D 55, 1971 (1997)
• The eth formalism in numerical relativity
  R. Gómez, L. Lehner, P. Papadopoulos, and J. Winicour
  Class.Quant.Grav. 14, 977-990 (1997), gr-qc/9702002
• Cauchy-characteristic Evolution and Waveforms
  Nigel T. Bishop, Roberto Gómez, Paulo R. Holvorcem, Richard A. Matzner, Philippos Papadopoulos, and Jeffrey Winicour
  J. Comp. Phys. 136, 140 (1997)
• Fuzzy spacetime from a null-surface version of GR
  S. Frittelli, C. N. Kozameh, E. T. Newman, C. Rovelli, R. S. Tate
  Invited contribution to the Class. Quantum Grav. special issue dedicated to Andrzej Trautman,
  Class.Quant.Grav. 14, A143-A154 (1997), gr-qc/9603061

1996

• Cauchy-characteristic extraction in numerical relativity
  N. Bishop, R. Gómez, L. Lehner, J. Winicour
  Phys. Rev. D 54, 6153 (1996,) gr-qc/9705033
• Gravitational Instability of a Kink
  Willians Barreto, Roberto Gómez, Luis Lehner, and Jeffrey Winicour
  Phys. Rev. D 54, 3834 (1996)
• Cauchy-characteristic evolution of Einstein-Klein-Gordon Systems.
  Roberto Gómez, Pablo Laguna, Philippos Papadopoulos, and Jeffrey Winicour
  Phys. Rev. D 54, 4719 (1996)
• Cauchy-characteristic matching: A new approach to radiation boundary conditions
  Nigel T. Bishop, Roberto Gómez, Paulo R. Holvorcem, Richard A. Matzner, Philippos Papadopoulos, and Jeffrey Winicour
  Phys. Rev. Lett. 76, 4303 (1996)
• The complete spectrum of the area from recoupling theory in loop quantum gravity
  Simonetta Frittelli, Luis Lehner, and Carlo Rovelli
  Class.Quant.Grav. 13, 2921-2932 (1996), gr-qc/9608043
• First-order symmetric-hyperbolic Einstein equations with arbitrary fixed gauge
  Simonetta Frittelli and Oscar A. Reula
  Phys. Rev. Lett. 76, 4667-4670 (1996), gr-qc/9605005

1995

• Toroidal black holes and topological censorship
  Stuart L. Shapiro, Saul A. Teukolsky and Jeffrey Winicour
  Phys. Rev. D 52, 6982 (1995)
• GR via Characteristic Surfaces
  Simonetta Frittelli, Carlos Kozameh, and Ted Newman
  J. Math. Phys. 36, 4984-5004 (1995), gr-qc/9502028
• Linearized Einstein theory via null surfaces
  Simonetta Frittelli, Carlos N. Kozameh, and Ezra T. Newman
  J. Math. Phys. 36, 5005-5022 (1995), gr-qc/9502026
• Lorentzian Metrics from Characteristic Surfaces
  Simonetta Frittelli, Carlos Kozameh, and Ted Newman
  J. Math. Phys. 36, 4975-4983 (1995), gr-qc/9502025
• Stereographic Coordinate Patches.
  Program listing also available.
  R. Gómez, P. Papadopoulos, and J. Winicour
  BBH working paper
• Finite Differencing on the Sphere.
  Contributed talk in the Seventh Marcel Grossman meeting in Relativity (1995).

1994

• Null Cone Evolution of Axisymmetric Vacuum Spacetimes.
  R. Gómez, P. Papadopoulos, and J. Winicour
  J. Math. Phys. 35, 4184 (1994), gr-qc/0006081
• Classical and quantum dynamics of the Faraday lines of force.
  S. Frittelli, S. Koshti, E. T. Newman, and C. Rovelli
  Phys. Rev. D 49, 6883 (1994)
• Newman-Penrose constants and the tails of self-gravitating waves.
  R. Gómez, B. Schmidt, and J. Winicour
  Phys. Rev. D 49, 2828 (1994)
• On the Newtonian Limit of General Relativity
  Simonetta Frittelil and Oscar Reula
  Commun. Math. Phys. 166 (1994) 221, gr-qc/9506077

1993

• High Amplitude Limit of Scalar Power.
  R. Gómez and J. Winicour
  Phys. Rev. D 48, 2653 (1993)
• Post-Newtonian Behavior of the Bondi Mass.
  R. Gómez, P. Reilly, J. Winicour, and R. A. Isaacson
  Phys. Rev. D 47, 3292 (1993)
• High Amplitude Behavior of Gravitational Energy.
  R. Gómez and J. Winicour
  In Topics in Quantum Mechanics and Beyond, Essays in Honor of Louis Witten on His Retirement,
  eds. F.Mansouri and J. Scanio, World Scientific, (1993)

1992

• Numerical Asymptotics.
  R. Gómez and J. Winicour
  In Approaches to Numerical Relativity, editor R.d'Inverno, Cambridge University Press (1992)
• Gravitational wave forms at finite distances and at null infinity.
  R. Gómez and J. Winicour
  Phys. Rev. D 45, 2776 (1992)
• Asymptotics of gravitational collapse of scalar waves.
  R. Gómez and J. Winicour
  J. Math. Phys. 33, 1445 (1992)
• Evolution of Scalar Fields from Characteristic Data
  R. Gómez, J. Winicour, and R. A. Isaacson
  J. Comp. Phys. 98, 11 (1992)

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Last Updated: September 16, 2005
Direct questions to Roberto Gómez, gomez@psc.edu