Charles D. Bailyn is the A. Bartlett Giamatti Professor of Astronomy and Physics at Yale University. He is currently serving as dean of faculty at Yale-NUS College in Singapore. He was awarded the 2009 Bruno Rossi Prize from the American Astronomical Society for his work on measuring the masses of black holes.

"This book goes straight to the heart of astronomical intuition and evidence about black holes. Written in a highly accessible style, it provides enough information to educate an undergraduate astronomy or physics major without going into the many details required in a graduate class. I think students will greatly enjoy this book and derive significant insight from it."—Coleman Miller, University of Maryland, College Park

• PREFACE xi 1. Introducing Black Holes: Event Horizons and Singularities 1 1.1 Escape Velocity and Event Horizons 3 1.2 The Metric 6 1.3 What Is a Black Hole? 11 2. Accretion onto a Black Hole 13 2.1 Spherical Accretion and the Eddington Limit 14 2.2 Standard Accretion Disks 17 2.3 Radiatively Inefficient Accretion Flows 23 2.4 Accretion Instabilities 24 2.5 Radiation Emission Mechanisms 27 2.6 Radiative Transfer 32 2.7 The alpha-Disk 35 3. Outflows and Jets 43 3.1 Superluminal Motion 45 3.2 Jet Physics and Magnetohydrodynamics 48 4. Stellar-Mass Black Holes 53 4.1 X-Ray Binaries 54 4.2 Varieties of X-Ray Binaries 58 4.3 X-Ray Accretion States 60 4.4 Compact Objects 63 4.5 Mass Measurements in X-Ray Binaries 68 4.6 Are High-Mass Compact Objects Black Holes? 73 4.7 Isolated Stellar-Mass Black Holes 76 4.8 The Chandrasekhar Limit 79 5. Supermassive Black Holes 84 5.1 Discovery of Quasars 85 5.2 Active Galaxies and Unification 88 5.3 Superluminal Jets and Blazars 94 5.4 Nonaccreting Central Black Holes 98 5.5 Mass Determinations for Extragalactic SMBHs 99 6. Formation and Evolution of Black Holes 106 6.1 Stellar-Mass Black Holes 107 6.2 Supermassive Black Holes 119 7. Do Intermediate-Mass Black Holes Exist? 127 7.1 Ultraluminous X-Ray Binaries 127 7.2 Black Holes in Star Clusters and Low-Mass Galaxies 132 8. Black Hole Spin 135 8.1 The Innermost Stable Circular Orbit 137 8.2 Observations of the ISCO through Line Emission 139 8.3 Observations of the ISCO through Thermal Emission 144 8.4 Consequences of Spin for Jets and Other Phenomena 147 9. Detecting Black Holes through Gravitational Waves 150 9.1 Gravitational Waves and Their Effects 152 9.2 Binary Pulsars 156 9.3 Direct Detection of Gravity Waves 158 9.4 Detecting Astrophysical Signals 163 10. Black Hole Exotica 167 10.1 Hawking Radiation 167 10.2 Primordial Black Holes 171 10.3 Wormholes 174 10.4 Multiverses 176 GLOSSARY 179 INDEX 187

Charles D. Bailyn is the A. Bartlett Giamatti Professor of Astronomy and Physics at Yale University. He is currently serving as dean of faculty at Yale-NUS College in Singapore. He was awarded the 2009 Bruno Rossi Prize from the American Astronomical Society for his work on measuring the masses of black holes.

"This book goes straight to the heart of astronomical intuition and evidence about black holes. Written in a highly accessible style, it provides enough information to educate an undergraduate astronomy or physics major without going into the many details required in a graduate class. I think students will greatly enjoy this book and derive significant insight from it."—Coleman Miller, University of Maryland, College Park

• PREFACE xi 1. Introducing Black Holes: Event Horizons and Singularities 1 1.1 Escape Velocity and Event Horizons 3 1.2 The Metric 6 1.3 What Is a Black Hole? 11 2. Accretion onto a Black Hole 13 2.1 Spherical Accretion and the Eddington Limit 14 2.2 Standard Accretion Disks 17 2.3 Radiatively Inefficient Accretion Flows 23 2.4 Accretion Instabilities 24 2.5 Radiation Emission Mechanisms 27 2.6 Radiative Transfer 32 2.7 The alpha-Disk 35 3. Outflows and Jets 43 3.1 Superluminal Motion 45 3.2 Jet Physics and Magnetohydrodynamics 48 4. Stellar-Mass Black Holes 53 4.1 X-Ray Binaries 54 4.2 Varieties of X-Ray Binaries 58 4.3 X-Ray Accretion States 60 4.4 Compact Objects 63 4.5 Mass Measurements in X-Ray Binaries 68 4.6 Are High-Mass Compact Objects Black Holes? 73 4.7 Isolated Stellar-Mass Black Holes 76 4.8 The Chandrasekhar Limit 79 5. Supermassive Black Holes 84 5.1 Discovery of Quasars 85 5.2 Active Galaxies and Unification 88 5.3 Superluminal Jets and Blazars 94 5.4 Nonaccreting Central Black Holes 98 5.5 Mass Determinations for Extragalactic SMBHs 99 6. Formation and Evolution of Black Holes 106 6.1 Stellar-Mass Black Holes 107 6.2 Supermassive Black Holes 119 7. Do Intermediate-Mass Black Holes Exist? 127 7.1 Ultraluminous X-Ray Binaries 127 7.2 Black Holes in Star Clusters and Low-Mass Galaxies 132 8. Black Hole Spin 135 8.1 The Innermost Stable Circular Orbit 137 8.2 Observations of the ISCO through Line Emission 139 8.3 Observations of the ISCO through Thermal Emission 144 8.4 Consequences of Spin for Jets and Other Phenomena 147 9. Detecting Black Holes through Gravitational Waves 150 9.1 Gravitational Waves and Their Effects 152 9.2 Binary Pulsars 156 9.3 Direct Detection of Gravity Waves 158 9.4 Detecting Astrophysical Signals 163 10. Black Hole Exotica 167 10.1 Hawking Radiation 167 10.2 Primordial Black Holes 171 10.3 Wormholes 174 10.4 Multiverses 176 GLOSSARY 179 INDEX 187