What Does a Black Hole Look Like?

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 a-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