Physics of the interstellar and intergalactic medium

Cover......Page 1
Contents......Page 8
Preface......Page 18
1. Introduction......Page 20
1.1 Organization of the ISM: Characteristic Phases......Page 23
1.3 Energy Densities......Page 28
2.1 Collisional Rate Coefficients......Page 30
2.2 Inverse-Square Law Forces: Elastic Scattering......Page 31
2.4 Ion–Neutral Collision Rates......Page 36
2.5 Electron–Neutral Collision Rates......Page 39
2.6 Neutral–Neutral Collision Rates......Page 40
3.1 Partition Functions......Page 41
3.2 Detailed Balance: The Law of Mass Action......Page 42
3.3 Ionization and Recombination......Page 43
3.4 Saha Equation......Page 44
3.6 Detailed Balance: Ratios of Cross Sections......Page 45
3.7 Example: Three-Body Recombination......Page 47
3.8 Departure Coefficients......Page 49
4.2 Configurations......Page 51
4.3 Spectroscopic Terms......Page 52
4.5 Designation of Energy Levels for Atoms and Ions: Spectroscopic Notation......Page 53
4.6 Hyperfine Structure: Interaction with Nuclear Spin......Page 55
4.8 Further Reading......Page 56
5.1 Diatomic Molecules......Page 57
5.2 * Energy Levels of Nonlinear Molecules......Page 66
5.3 * Zeeman Splitting......Page 70
5.4 Further Reading......Page 71
6.1 Emission and Absorption of Photons......Page 72
6.2 Absorption Cross Section......Page 74
6.3 Oscillator Strength......Page 75
6.4 Intrinsic Line Profile......Page 76
6.5 Doppler Broadening: The Voigt Line Profile......Page 77
6.6 Transition from Doppler Core to Damping Wings......Page 78
6.7 Selection Rules for Radiative Transitions......Page 79
7.1 Physical Quantities......Page 82
7.2 Equation of Radiative Transfer......Page 84
7.4 Integration of the Equation of Radiative Transfer......Page 85
7.5 Maser Lines......Page 87
8.1 HI Emissivity and Absorption Coefficient......Page 89
8.2 Optically Thin Cloud......Page 91
8.3 Spin Temperature Determination Using Background Radio Sources......Page 92
9.1 Absorption Lines......Page 94
9.3 Flat Portion of the Curve of Growth, 10 ≲  τ0 ≲  τdamp......Page 96
9.4 Damped Portion of the Curve of Growth, τ0 ≳ τdamp......Page 98
9.6 Doublet Ratio......Page 100
9.7 Lyman Series of Hydrogen: Ly 945;, Ly β, Ly γ, . . .......Page 102
9.8 Lyman Limit......Page 103
9.9 H[sub(2)]: Lyman and Werner Bands......Page 104
9.10 \"Metal\" Lines......Page 105
9.11 Abundances in HI Gas......Page 109
10.1 Free–Free Emission (Bremsstrahlung)......Page 111
10.2 * Gaunt Factor......Page 112
10.4 Free–Free Absorption......Page 114
10.5 Emission Measure......Page 115
10.7 Radio Recombination Lines......Page 116
11.1 Dispersion Relation for Cold Plasmas......Page 120
11.2 Dispersion......Page 121
11.3 Faraday Rotation......Page 124
11.4 * Refraction......Page 128
11.5 * Scintillation......Page 130
11.6 * Interstellar Electron Density Power Spectrum......Page 132
11.7 * Extreme Scattering Events......Page 135
12.1 Galactic Synchrotron Radiation......Page 138
12.2 Cosmic Microwave Background Radiation......Page 139
12.4 Infrared Emission from Dust......Page 140
12.5 Starlight in an HI Region......Page 142
12.7 Radiation Field in a Photodissociation Region near a Hot Star......Page 144
13. Ionization Processes......Page 154
13.1 Photoionization......Page 155
13.2 Auger Ionization and X-Ray Fluorescence......Page 158
13.3 Secondary Ionizations......Page 159
13.5 Cosmic Ray Ionization......Page 161
14.1 Radiative Recombination......Page 164
14.2 Radiative Recombination of Hydrogen......Page 165
14.3 * Radiative Recombination: Helium......Page 173
14.4 Radiative Recombination: Heavy Elements......Page 177
14.5 Dielectronic Recombination......Page 178
14.6 Dissociative Recombination......Page 180
14.7 Charge Exchange......Page 181
14.8 Ion Neutralization by Dust Grains......Page 184
14.9 Ionization Balance in Collisionally Ionized Gas......Page 186
15.1 HII Regions as Strömgren Spheres......Page 189
15.2 Time Scales......Page 192
15.3 Neutral Fraction within an HII Region......Page 193
15.4 Dusty HII Regions with Radiation Pressure......Page 194
15.5 Ionization of Helium and Other Elements......Page 199
15.6 Planetary Nebulae......Page 202
15.7 * Escape of Lyman α......Page 203
15.8 * Ionization by Power-Law Spectra......Page 207
16.1 HI Regions: Ionization of Metals......Page 209
16.2 Cool HI Regions: Ionization of Hydrogen......Page 211
16.3 Warm HI Regions......Page 212
16.4 Diffuse Molecular Gas......Page 213
16.5 Dense Molecular Gas: Dark Clouds......Page 215
17.1 Two-Level Atom......Page 217
17.2 Critical Density n[sub(crit,u)]......Page 218
17.3 Example: HI Spin Temperature......Page 219
17.4 Example: C II Fine Structure Excitation......Page 222
17.5 * Three-Level Atom......Page 224
17.7 * Measurement of Density and Pressure Using CI......Page 225
18. Nebular Diagnostics......Page 230
18.1 Temperature Diagnostics: Collisionally Excited Optical/UV Lines......Page 231
18.2 Density Diagnostics: Collisionally Excited Optical/UV Lines......Page 236
18.3 Density Diagnostics: Fine-Structure Emission Lines......Page 237
18.4 * Other Diagnostic Methods......Page 239
18.5 Abundance Determination from Collisionally Excited Lines......Page 241
18.7 * Ionization/Excitation Diagnostics: The BPT Diagram......Page 242
19.1 Escape Probability Approximation......Page 246
19.2 Homogeneous Static Spherical Cloud......Page 248
19.3 Example: CO J = 1–0......Page 249
19.4 * LVG Approximation: Hubble Flow......Page 251
19.5 Escape Probability for Turbulent Clouds......Page 252
19.6 CO 1–0 Emission as a Tracer of H[sub(2)] Mass: CO \"X-Factor\"......Page 254
20.1 UV Pumping by Continuum......Page 256
20.2 * Infrared Pumping: OH......Page 258
20.3 * UV Pumping by Line Coincidence: Bowen Fluorescence......Page 259
21. Interstellar Dust: Observed Properties......Page 262
21.1 Interstellar Extinction......Page 263
21.2 Parametric Fits to the Extinction Curve......Page 266
21.3 Polarization by Interstellar Dust......Page 267
21.4 Scattering of Starlight by Interstellar Dust......Page 269
21.6 * Purcell Limit: Lower Limit on Dust Volume......Page 270
21.7 Infrared Emission......Page 273
21.8 * Luminescence......Page 274
22.1 Cross Sections and Efficiency Factors......Page 275
22.2 Dielectric Function and Refractive Index......Page 276
22.3 Electric Dipole Limit: Size << λ......Page 278
22.4 Limiting Behavior at Long Wavelengths......Page 279
22.5 Sizes Comparable to Wavelength: Mie Theory......Page 280
22.6 * Nonspherical Particles......Page 283
22.7 Interstellar Grains......Page 285
23.1 Abundance Constraints......Page 290
23.2 Presolar Grains in Meteorites......Page 293
23.3 Observed Spectral Features of Dust......Page 294
23.4 Silicates......Page 298
23.5 Polycyclic Aromatic Hydrocarbons......Page 301
23.6 * Graphite......Page 304
23.9 * Fullerenes......Page 305
23.10 Models for Interstellar Dust......Page 306
24.1 Heating and Cooling of \"Classical\" Dust Grains......Page 312
24.2 Heating and Cooling of Ultrasmall Dust Grains: Temperature Spikes......Page 317
24.3 Infrared Emission from Grains......Page 320
24.4 Collisionally Heated Dust......Page 322
25.1 Collisional Charging......Page 323
25.2 Photoelectric Emission......Page 324
25.4 * Secondary Electron Emission......Page 326
25.5 * Electron Field Emission......Page 328
25.7 Sputtering in Hot Gas......Page 329
26.1 Translational Motion......Page 331
26.2 Rotational Motion......Page 334
26.3 * Alignment of Interstellar Dust......Page 337
27.1 Heating by Photoionization......Page 342
27.2 Other Heating Processes......Page 344
27.3 Cooling Processes......Page 346
27.4 Thermal Equilibrium......Page 349
27.5 Emission Spectrum of an H II Region......Page 351
27.6 Observed Temperatures in H II Regions......Page 352
28.1 Trapezium Stars......Page 353
28.2 Distribution of Ionized Gas......Page 354
28.4 Gas Kinematics......Page 355
28.5 PIGS, Proplyds, and Shadows......Page 357
29.1 21-cm Line Observations......Page 358
29.2 Distribution of the HI......Page 359
29.3 Zeeman Effect......Page 360
29.5 Infrared Emission......Page 362
30.1 Heating: Starlight, Cosmic Rays, X Rays, and MHD Waves......Page 364
30.2 Photoelectric Heating by Dust......Page 365
30.3 Cooling: [C II] 158 µm, [OI] 63 µm, and Other Lines......Page 366
30.4 Two \"Phases\" for H I in the ISM......Page 368
30.5 Emission Spectrum of an H I Cloud......Page 370
31.1 Gas-Phase Formation of H[sub(2)]......Page 371
31.2 Grain Catalysis of H[sub(2)]......Page 372
31.3 Photodissociation of H[sub(2)]......Page 373
31.4 Self-Shielding......Page 375
31.5 * Excitation of Vibration and Rotation by UV Pumping......Page 376
31.6 * Rotational Level Populations......Page 377
31.7 * Structure of a Photodissociation Region......Page 379
31.8 Dense PDRs......Page 383
32.1 Taxonomy and Astronomy......Page 384
32.3 Molecular Radio Lines......Page 389
32.4 FIR Emission from Dust......Page 390
32.5 γ rays......Page 391
32.6 * Compact, Ultracompact, and Hypercompact HII Regions......Page 392
32.9 Size–Linewidth Relation in Molecular Clouds......Page 393
32.10 Magnetic Fields in Molecular Clouds......Page 396
32.11 Energy Dissipation in Molecular Clouds......Page 398
33. Molecular Clouds: Chemistry and Ionization......Page 400
33.1 Photoionization and Photodissociation of Molecules......Page 402
33.2 * Ion–Molecule Chemistry in Cold Gas......Page 403
33.3 * The CH[sup(+)] Problem......Page 406
34.1 Radiative Cooling......Page 408
34.2 Radiative Cooling Time......Page 411
34.3 * Thermal Conduction......Page 412
34.4 * Cloud Evaporation in Hot Gas......Page 413
34.5 * Conduction Fronts......Page 414
35.1 Mass Conservation......Page 416
35.2 Conservation of Momentum: MHD Navier-Stokes Equation......Page 417
35.3 Heating and Cooling......Page 419
35.4 Electrodynamics in a Conducting Fluid: Flux-Freezing......Page 420
35.5 * Virial Theorem......Page 422
36.1 Sources of Interstellar Shocks......Page 424
36.2 Jump Conditions: Rankine-Hugoniot Relations......Page 425
36.4 * Collisionless Shocks......Page 431
36.6 * Two-Fluid MHD Shocks in Low Fractional Ionization Gas......Page 433
37.1 * Ionization Fronts: R-Type and D-Type......Page 439
37.2 * Expansion of an H II Region in a Uniform Medium......Page 443
37.3 * Photodissociation Fronts......Page 446
38.1 * Winds from Hot Stars: Stellar Wind Bubbles......Page 449
38.2 * Winds from Cool Stars......Page 453
38.3 * Stellar Wind Bow-Shock......Page 454
39.1 Evolution of a Supernova Remnant in a Uniform ISM......Page 456
39.2 * Overlapping of SNRs......Page 462
39.3 * Supernova Remnants in an Inhomogeneous Medium......Page 463
39.4 Three-Phase Model of the ISM......Page 464
40.1 Cosmic Ray Energy Spectrum and Composition......Page 467
40.2 * Theory of Diffusive Shock Acceleration......Page 469
40.3 * Injection Problem......Page 471
40.4 * Upper Limits on Cosmic Ray Energy......Page 473
40.5 * Cosmic Ray Propagation......Page 474
40.7 * Gamma Ray Emission from Interstellar Clouds......Page 475
40.8 * [sup(26)]Al in the ISM......Page 476
40.9 * Positrons and Positronium in the ISM......Page 477
41.1 Gravitational Instability: Jeans Instability......Page 478
41.2 * Parker Instability......Page 480
41.3 Insights from the Virial Theorem......Page 483
41.4 Magnetic Flux Problem: Ambipolar Diffusion......Page 486
41.5 Angular Momentum Problem......Page 488
41.7 Radiation Pressure......Page 490
42.1 Collapse of Cores to form Stars......Page 492
42.2 Class 0, I, II, and III Protostars......Page 493
42.3 Initial Mass Function......Page 495
42.4 Star Formation Rates......Page 497
42.5 Schmidt-Kennicutt Law......Page 498
A. List of Symbols......Page 500
B. Physical Constants......Page 503
C. Summary of Radiative Processes......Page 504
D. Ionization Potentials (eV)......Page 508
E. Energy-Level Diagrams......Page 509
F. Collisional Rate Coefficients......Page 523
G. Semiclassical Atom......Page 530
H. Debye Length for a Plasma......Page 532
I. Heuristic Model for Ion–Electron Inelastic Scattering......Page 533
J. Virial Theorem......Page 535
Bibliography......Page 538
B......Page 556
C......Page 557
D......Page 558
F......Page 559
H......Page 560
I......Page 561
M......Page 562
O......Page 563
P......Page 564
S......Page 565
Z......Page 567