ACTIVE GALACTIC NUCLEI: FROM THE CENTRAL BLACK HOLE TO THE GALACTIC ENVIRONMENT

Transcription

1 Julian H. Krolik ACTIVE GALACTIC NUCLEI: FROM THE CENTRAL BLACK HOLE TO THE GALACTIC ENVIRONMENT PRINCETON UNIVERSITY PRESS Princeton, New Jersey

2 Preface Guide for Readers xv xix 1. What Are Active Galactic Nuclei? And Why- Does Anyone Care? What Makes Them Interesting? What Exactly Are We Talking About? The Most Salient Properties of AGNs Very small angular size High luminosity Broad-band continuum emission Emission lines \ Variability Polarization Radio emission AGN Nomenclature How to Find AGNs Optical Color Optical Emission Lines Radio Flux The 3C catalog and the confusion limit Optical identifications and the discovery of quasars Subsequent surveys X-rays Infrared rays 37

3 2.7 Merged Catalogs and Their Flux Limits Evolution Source Counts Formalism AGN source counts in the real world Radio source counts Optical source counts X-ray source counts In which band do the counts go the "deepest"? The V/V max Test Luminosity Function as a Function of Redshift Parameterizing Evolution Can One Solve the Population Equation? Global Energetics and Black Holes The Mean Energy Density of AGN Light Energy Production Efficiency and Remnant Masses Rees's Flow Chart Causality bounds Variability timescales The flow chart Evidence for Massive Black Holes in Galaxies Expected response of stars and interstellar gas to a large nuclear mass Observational tests Black Hole Physics Particle Mechanics in the Vicinity of Black Holes General properties of relativistic particle mechanics Particle motion in a spherically symmetric potential Motion in the Schwarzschild metric Motion in the Kerr metric 103 vi

4 5.2 Electromagnetic Fields Introductory comments Surface resistance The rotating black hole battery Photon Propagation Spherical Accretion Bondi Accretion The Eddington Limit Nonadiabatic Accretion Critical point structure Optical depth and photon trapping Thermal instability Accretion Disks and the Optical/Ultraviolet Continuum Fundamental Equations of Thin Disks What Is the Torque? Viscosity? Magnetized winds? Turbulent Maxwell stresses: the Velikhov-Chandrasekhar-Balbus-Hawley instability Time-Steady Disks Radial structure: angular momentum and energy conservation Relativistic effects LTE spectrum Vertical structure Advection-dominated disks, Inside the marginally stable orbit Time-Dependent Disks Characteristic timescales Stability 165 VII

5 7.5 Emitted Spectrum Opacity mechanisms Thermalization Emergent spectrum from a vertically isothermal disk Emergent spectrum from a disk with vertical temperature gradients Angle dependence Polarization Observational Tests The big bump and disk model fits Lyman edge features Polarization Variability X-ray and 7-ray Emission Observed Spectra Radio-quiet AGNs Radio-loud lobe-dominated AGNs Radio-loud core-dominated AGNs Observed variability Radiation Physics: Bremsstrahlung and Inverse Compton Scattering Bremsstrahlung 203 \ Inverse Compton scattering 206 ', 8.3 Output Spectra from Inverse Compton Scattering Optically thin Optically thick Electron-Positron Pair Physics Pair production processes and their rates Pair annihilation Peculiarities of pair dynamics Self-Consistent Equilibria Thermal electrons Nonthermal electrons 232 viii

6 8.6 Sources of Energetic Electrons Hot thermal electrons Relativistic electrons X-ray and 7-ray Propagation The nature of soft X-ray opacity Fe Ka emission Consequences of Comptonization and pair production for 7-rays X-ray reflection Comparison with Observations X-rays rays Radio Emission and Jets Phenomenology Relative strength of radio emission Morphology Spectrum Polarization Variability Synchrotron Theory Optically thin emission Polarization \ Estimating the magnetic field strength: the minimum energy argument Optically thick emission Spontaneous and stimulated Compton scattering in optically thick synchrotron sources Jets Content Acceleration and collimation Propagation and morphology Jet radiation 301 ix

7 10, Emission Lines Observables Line lists and relative strengths Line profiles Classification on the basis of emission line properties Physical Overview Line Production by Photo-ionization Geometry and internal dynamics Ionization equilibrium Thermal equilibrium Radiation transfer Excited state population equilibrium, recombination cascade, and the approach to thermodynamic equilibrium Conditions for Achieving Equilibrium Results of Photo-ionization Calculations The T-E diagram Generic models Model construction Shocks Internal shock structure Self-generated photo-ionization Emergent spectrum Line-Emitting Gas Dynamics and Life Cycle Intrinsic Absorption and Outflows Phenomenology Physical Conditions in the Absorbing Gas The Magnitude of the Problem Dynamics Thermally driven winds Magnetically driven winds Radiation pressure driven winds 414

8 12. Anisotropic Appearance and Unification of Disparate AGN Varieties General Principles Mechanisms Producing Intrinsically Anisotropic Emission Nonspherical relativistic motion Angle-dependent disk emission Angle-Dependent Obscuration Mechanisms Mirrors and Screens: or, How to See AGNs from Another Side Polarization Reflection without dilution Emission lines Infrared continuum Spectra versus images Unification of Flat-Spectrum Compact Radio Sources with Steep-Spectrum Extended Sources Luminosity function of compact radio sources Jet length and speed Depolarization Unification of Radio-Quiet Broad Line and Narrow Line AGNs via Toroidal Obscuration Mirrors \ Screens Energy-dependent obscuration Relative numbers of type 1 and type 2 Seyfert galaxies Extrapolation to higher luminosity? Unification of Radio-Loud Quasars and Radio Galaxies via Toroidal Obscuration Mirrors Screens: infrared reradiation Relative numbers of radio-loud quasars and radio galaxies 463

9 13. Properties of AGN Host Galaxies Methodology Imaging the host Sample definition Host Morphology Sample selection Host morphology and existence of an AGN Host morphology and radio loudness Fine points of host morphology: bars and other disturbances Host Luminosity Host Interstellar Medium Signals Surveys Orientation Evolutionary State Environment Impact of the Nucleus on the Host Onset and Fueling Introduction The Timescale Problem Creation and growth of the black hole Heavy element abundances Black hole centralization and multiple black holes Basic Fueling Mechanisms Gravitational forces Hydrodynamic dissipation Magnetic forces Poynting-Robertson drag Stellar-interstellar mass exchange Gas heating and cooling Triggers and Scenarios 511 xii

10 Cooling flows Axisymmetric collapse enhanced by magnetic braking Bar-driven inflow Encounters Some Open Questions Where We Stand Accomplishments The Future 531 Appendix A: Basic General Relativity 533 Appendix B: Basic Magnetohydrodynamics 537 Appendix C: Shocks and Other Discontinuities 542 Appendix D: Luminosity Functions and Other Population Statistics 552 D.I More Sophisticated Estimates of the Luminosity Function 552 D.2 Correlations and Multivariate Probability Distributions 555 Appendix E: The Tensor Virialjheorem 559 Appendix F: Kinematics in an Expanding Universe 566 References 573 Index 589 xiii