Gravitational Radiation, Luminous Black Holes, and Gamma-Ray Burst Supernovae Blackholesandgravitationalradiationaretwoofthemostdramaticpredictionsof general relativity. The quest for rotating black holes – discovered by Roy P. Kerr asexactsolutionstotheEinsteinequations–isoneofthemostexcitingchallenges currently facing physicists and astronomers. Gravitational Radiation, Luminous Black Holes and Gamma-ray Burst Super- novae takes the reader through the theory of gravitational radiation and rotating blackholes,andthephenomenologyofGRBsupernovae.Topicscoveredinclude Kerr black holes and the frame-dragging of spacetime, luminous black holes, compact tori around black holes, and black hole–spin interactions. It concludes withadiscussionofprospectsforgravitational-wavedetectionsofalong-duration burstingravitationalwavesasamethodofchoiceforidentifyingKerrblackholes in the universe. This book is ideal for a special topics graduate course on gravitational-wave astronomy and as an introduction to those interested in this contemporary devel- opment in physics. Maurice H. P. M. van Putten studied at Delft University of Technology, The Netherlands and received his Ph.D. from the California Institute of Technol- ogy. He has held postdoctoral positions at the Institute of Theoretical Physics at the University of California at Santa Barbara, and the Center for Radiophysics and Space Research at Cornell University. He then joined the faculty of the Massachusetts Institute of Technology and became a member of the new Laser InterferometricGravitational-waveObservatory(MIT-LIGO),whereheteachesa special-topic graduate course based on his research. Professor van Putten’s research in theoretical astrophysics has spanned a broad range of topics in relativistic magnetohydrodynamics, hyperbolic formulations of general relativity, and radiation processes around rotating black holes. He has led global collaborations on the theory of gamma-ray burst supernovae from rotating black holes as burst sources of gravitational radiation. His theory describes a unique link between gravitational waves and Kerr black holes, two of the most dramaticpredictionsofgeneralrelativity.Discoveryoftriplets–gamma-rayburst supernovae accompanied by a long-duration gravitational-wave burst – provides a method for calorimetric identification of Kerr black holes in the universe. Gravitational Radiation, Luminous Black Holes, and Gamma-Ray Burst Supernovae MAURICE H. P. M. VAN PUTTEN MassachusettsInstituteofTechnology cambridge university press Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo Cambridge University Press TheEdinburghBuilding,Cambridgecb22ru,UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521849609 © M. H. P. M. van Putten 2005 Thispublicationisincopyright.Subjecttostatutoryexceptionandtotheprovisionof relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. 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To my parents Anton and Maria, and Michael, Pascal, and Antoinette Contents Foreword page xi Acknowledgments xii Introduction xiii Notation xvii 1 Superluminal motion in the quasar 3C273 1 1.1 Lorentz transformations 1 1.2 Kinematic effects 5 1.3 Quasar redshifts 6 1.4 Superluminal motion in 3C273 7 1.5 Doppler shift 9 1.6 Relativistic equations of motion 9 ∗ 2CurvedspacetimeandSgrA 13 2.1Theacceleratedletter“ L”14 2.2Thelengthoftimeliketrajectories15 2.3Gravitationalredshift16 2.4Spacetimearound astar18 2.5 Mercury’s perihelion precession 20 ∗ 2.6 A supermassive black hole in SgrA 22 3 Parallel transport and isometry of tangent bundles 26 3.1 Covariant and contravariant tensors 27 3.2 The metric g 29 ab 3.3 The volume element 30 3.4 Geodesic trajectories 31 3.5 The equation of parallel transport 32 3.6 Parallel transport on the sphere 34 3.7 Fermi–Walker transport 34 3.8 Nongeodesic observers 35 3.9 The Lie derivative 39 vii viii Contents 4 Maxwell’s equations 43 4.1 p-forms and duality 43 4.2 Geometrical interpretation of F 44 ab 4.3 Two representations of F 46 ab 4.4 Exterior derivatives 47 4.5 Stokes’ theorem 48 4.6 Some specific expressions 49 4.7 The limit of ideal MHD 50 5 Riemannian curvature 55 5.1 Derivations of the Riemann tensor 55 5.2 Symmetries of the Riemann tensor 57 5.3 Foliation in spacelike hypersurfaces 58 5.4 Curvature coupling to spin 59 5.5 The Riemann tensor in connection form 62 5.6 The Weyl tensor 64 5.7 The Hilbert action 64 6 Gravitational radiation 67 6.1 Nonlinear wave equations 69 6.2 Linear gravitational waves in h 72 ij 6.3 Quadrupole emissions 75 6.4 Summary of equations 79 7 Cosmological event rates 81 7.1 The cosmological principle 82 7.2 Our flat and open universe 83 7.3 The cosmological star-formation rate 85 7.4 Background radiation from transients 85 7.5 Observed versus true event rates 86 8 Compressible fluid dynamics 89 8.1 Shocks in 1D conservation laws 91 8.2 Compressible gas dynamics 94 8.3 Shock jump conditions 95 8.4 Entropy creation in a shock 98 8.5 Relations for strong shocks 98 8.6 The Mach number of a shock 100 8.7 Polytropic equation of state 101 8.8 Relativistic perfect fluids 103 9 Waves in relativistic magnetohydrodynamics 110 9.1 Ideal magnetohydrodynamics 112 9.2 A covariant hyperbolic formulation 113 Contents ix 9.3 Characteristic determinant 115 9.4 Small amplitude waves 117 9.5 Right nullvectors 118 9.6 Well-posedness 122 9.7 Shock capturing in relativistic MHD 125 9.8 Morphology of a relativistic magnetized jet 132 10 Nonaxisymmetric waves in a torus 138 10.1 The Kelvin–Helmholtz instability 139 10.2 Multipole mass-moments in a torus 141 10.3 Rayleigh’s stability criterion 142 10.4 Derivation of linearized equations 142 10.5 Free boundary conditions 144 10.6 Stability diagram 145 10.7 Numerical results 146 10.8 Gravitational radiation-reaction force 148 11 Phenomenology of GRB supernovae 152 11.1 True GRB energies 162 11.2 A redshift sample of 33 GRBs 164 11.3 True GRB supernova event rate 165 11.4 Supernovae: the endpoint of massive stars 168 11.5 Supernova event rates 174 11.6 Remnants of GRB supernovae 175 11.7 X-ray flashes 176 11.8 Candidate inner engines of GRB/XRF supernovae 177 12 Kerr black holes 179 12.1 Kerr metric 180 12.2 Mach’s principle 183 12.3 Rotational energy 183 12.4 Gravitational spin–orbit energy E=(cid:1)J 185 12.5 Orbits around Kerr black holes 187 12.6 Event horizons have no hair 189 12.7 Penrose process in the ergosphere 192 13 Luminous black holes 197 13.1 Black holes surrounded by a torus 197 13.2 Horizon flux of a Kerr black hole 199 13.3 Active black holes 202 14 A luminous torus in gravitational radiation 215 14.1 Suspended accretion 216 14.2 Magnetic stability of the torus 217 14.3 Lifetime and luminosity of black holes 222