Contents

Preface

Galaxies: an overview

• 1.1 Introduction 1
• 1.2 A brief history of galactic astronomy 2
  • Photometric models of the Milky Way 5
  • The nature of the spiral nebulae 10
  • Kinematic models of the Milky Way 15
  • Stellar populations 20
  • More recent developments 21

Astronomical Measurements

• 2.1 Positions, motions and coordinate systems 27
  • The equatorial system 27
  • Galactic coordinates 30
  • Parallax 31
  • Proper motions 34
  • Precession and nutation 35
  • Astrometric systems 37
• 2.2 Distances determined from velocities 38
  • Radial velocities 39
  • Distances from the movingcluster method 40
  • Secular parallaxes 42
  • Statistical parallaxes 45
• 2.3 Magnitudes and colors 46
  • Apparent magnitudes 47
  • Colors 52
  • Absolute magnitudes 56
  • Absolute energy distributions
  • and bolometric magnitudes 58
  • Mass-to-light ratios 60
  • Surface brightness and isophotal radii 61
• 2.4 Gravitational lensing 62
• 2.5 Archival data and catalogs 67
  • On-line resources 71
• Problems 74

The Properties of Stars

• 3.1 The masses of stars 76
  • The Mass of the Sun 77
  • Masses of binary stars 78
  • Visual binaries 78
  • Spectroscopic binaries 79
• 3.2 The radii of stars 82
  • Phase interferometry 82
  • Intensity interferometry 83
  • Speckle interferometry 83
  • Lunar occultations 84
  • Eclipsing binaries 84
  • Astrophysical estimates 86
• 3.3 Classification of stars 87
  • Novae 87
  • Pulsars 87
  • Classification of stellar spectra 88
  • The MK system 90
• 3.4 Physical interpretation of stellar spectra 94
• 3.5 Color-magnitude diagrams 102
  • Observed CM-diagrams 103
  • Luminosity and color as functions of spectral class 104
  • The physical properties of stars on the MS and RGB 109
• 3.6 The stellar luminosity function 109
  • Malmquist bias 111
  • Lutz-Kelker Bias 115
  • The general luminosity function 119
  • Cluster luminosity functions 119
  • Photometrically complete surveys 119
  • Proper-motion selected surveys 120
  • The luminosity function of a given MK spectral class 127
  • Catalogs of the nearby stars 130
• 3.7 Interstellar dust 131
  • Extinction and reddening 133
  • Reddening-free indices 138
  • Polarization of starlight by dust 140
  • Extinction of sightlines out of the Galaxy 140
• Problems 143

Morphology of Galaxies

• 4.1 Morphological classification of galaxies 146
  • The Hubble sequence 149
  • Effects of environment 157
  • The galaxy luminosity function 162
  • The field galaxy luminosity function 162
  • The cluster galaxy luminosity function 165
  • The luminosity function divided by morphological type 167
  • The Local Group 169
• 4.2 Surface Photometry of Galaxies 172
  • The night sky 173
  • Effect of seeing 176
  • Deprojecting galaxy images 179
• 4.3 Photometry of Elliptical Galaxies 185
  • Radial surface-brightness profiles of elliptical galaxies 185
  • cD galaxies 186
  • Dwarf elliptical galaxies 190
  • Centers of elliptical galaxies 191
  • Color and line-strength gradients in elliptical galaxies 193
  • Shapes of elliptical galaxies 194
  • Ellipticity 194
  • Deviations from ellipses 199
  • Fine structure 201
  • Correlations among global parameters of elliptical galaxies 204
  • The D_n - [Sigma]₀ correlation 209
  • Dwarf elliptical galaxies 209
• 4.4 Photometry of Disk Galaxies 210
  • Photometric effects of dust 211
  • Overall shapes of disk galaxies 212
  • Bulge-disk decomposition 214
  • Shapes of bulges 222
  • Color and metallicity gradients in disk galaxies 223
  • Spiral structure in disk galaxies 224
  • Barred galaxies 228
  • Vertical structure of bars 231
  • Rings in SB galaxies 233
  • Dust lanes in SB galaxies 234
  • Lop-sidedness in SB galaxies 234
• 4.5 Globular cluster systems 235
  • Globular cluster luminosity function 236
  • Specific frequency of globular clusters 237
  • Radial density profiles and shapes 238
  • Color distributions 239
• 4.6 Abnormal galaxies 241
  • Starbursting systems 241
  • Systems with active galactic nuclei 244
  • Host galaxies of AGN 250
  • The unified model of AGN 251
• Problems 255

Evolution of Stars and Stellar Populations

• 5.1 Stellar evolution and the CM diagram 259
  • Placing models in the CM diagram 262
  • Features in the CM diagram 263
  • Characteristic initial masses 267
  • Bounding curves in the CM diagram 274
  • Dependence of CM diagrams upon metallicity 276
  • The cosmic helium abundance 279
  • Simple numerical relations 279
  • Star formation 281
  • The initial mass function 283
  • Pulsating stars 287
  • Classical Cepheid variables 289
  • Mira variables 292
  • W Virginis stars 293
  • RR Lyrae stars 293
• 5.2 Synthesis of the chemical elements 296
  • Basic nuclear physics 296
  • Metal production at M_i < M_up 301
  • Supernovae 302
  • Metal production by core-collapse supernovae 303
  • Metal production by type Ia supernovae 305
• 5.3 Models of chemical enrichment 306
  • The closed-box model 306
  • The leaky-box model 308
  • The accreting-box model 313
• 5.4 Evolution of stellar populations 314
  • Analytical results 315
  • Numerical models of population evolution 317
• Problems 324

Star clusters

• 6.1 Globular clusters 327
  • Globular cluster stellar photometry 332
  • Color-magnitude diagrams 334
  • The main sequence and subgiant branch 335
  • The horizontal branch 337
  • Comparison with Theoretical CM diagrams 339
  • Globular cluster ages 344
  • Turnoff point ages 344
  • Isochrone fitting 345
  • The [Delta]V method 346
  • The [Delta](B-V) 347
  • Comparison with the age of the Universe 348
  • Variations in age 349
  • Metallicities of globular clusters 350
  • [Omega] Cen 351
  • The third parameter problem 352
  • Variations in helium abundance 353
  • Variations in other element abundances 353
  • Other candidates 354
  • Luminosity functions 354
  • Binary stars 359
  • Stellar remnants 361
  • White dwarfs 361
  • Neutron stars 362
  • Radial profiles 363
  • Large-scale properties 365
  • Luminosity segregation 367
  • Central cusps 369
  • Kinematics 371
  • Velocities of individual stars 371
  • Integrated-light kinematics 374
  • Proper motions 375
• 6.2 Open clusters 377
  • Color-magnitude diagrams 381
  • The ages and demise of open clusters 384
  • Structure and kinematics 386
  • Luminosity function 389
• Problems 392

The Cosmic Distance Scale

• 7.1 An introduction to cosmology 396
• 7.2 Absolute distance estimators 399
  • The Baade-Wesselink method 399
  • Application to supernovae 402
  • The Sunyaev-Zel'dovich effect 403
  • Distances from time delays 405
  • The ring around Supernova 1987A 406
  • Gravitational lens time delays 407
  • Water-maser proper-motions by VLBI 410
• 7.3 Relative distance estimators 414
  • Luminosities of variable stars 415
  • Luminosity functions 415
  • Globular clusters 416
  • Planetary nebulae 417
  • Novae and supernovae 419
  • Novae 419
  • Type Ia supernovae 420
  • Distances from galaxy kinematics 422
  • Spiral galaxies 422
  • Elliptical galaxies 425
  • Surface brightness fluctuations 426
• 7.4 Results 429
  • Distances within the Local Group 432
  • Distance to the Galactic center 432
  • Distance to the Large Magellanic Cloud 434
  • Distance to M31 435
  • Distances beyond the Local Group 437
  • Distance to the Virgo Cluster 437
  • Peculiar velocity field 439
  • The asymptotic Hubble constant 441
  • The deceleration parameter and cosmic density 444
  • Standard candles and rulers 444
  • Peculiar velocity field 447
• Problems 449

The Interstellar Media of Galaxies

• 8.1 How interstellar matter is detected 452
  • Absorption of starlight 452
  • Extreme UV and Xray observations 459
  • Optical emission lines 463
  • Hydrogen lines 463
  • Metal lines 464
  • Radio observations 468
  • The 21-cm line of atomic hydrogen 471
  • Rotation transitions of heteronuclear molecules 474
  • Synchrotron radiation 478
  • Radio-frequency bremsstrahlung and recombination lines 480
  • Dispersion and Rotation Measures 481
  • Gamma-ray emission 482
  • Radiation by dust 483
• 8.2 The ISM in Disk Galaxies 488
  • Global measures 493
  • HI and H₂ in disk galaxies 493
  • Radio-continuum and IR luminosities 496
  • Radial density profiles 498
  • Azimuthal distributions 500
  • Bars and oval distortions 500
  • Spiral structure 500
  • Lop-sidedness 502
  • Velocity fields of disks 505
  • Circular-speed curves 507
  • Kinematic warps 510
  • Oval distortions 512
  • S0 galaxies 513
  • Metallicities of disk galaxies 516
  • Magnetic fields 520
  • Star formation in disk galaxies 522
• 8.3 The ISM in elliptical galaxies 525
  • X-ray emitting plasma 525
  • Cool gas in ellipticals 527
• 8.4 Intergalactic gas 530
  • The Magellanic Stream 530
• Problems 533

The Milky Way's ISM

• 9.1 The kinematics of differential rotation 536
  • The naive (l,v) plot 536
  • Radii and distances from the (l,v) plot 540
  • Non-circular motion and the (l,v) plot 541
  • Axisymmetric expansion 541
  • Oval distortions 542
  • Spiral structure 544
  • Random motions 546
• 9.2 The large-scale distribution of HI and CO 549
  • The 21-cm line in emission 549
  • Measuring the spin temperature 553
  • CO lines in emission 554
  • The Milky Way's circular-speed curve 555
  • Radial distributions of HI and CO 559
  • Evidence for spiral structure 561
  • Vertical distributions of HI and CO 562
  • The middle disk 563
  • The outer disk 565
• 9.3 Other tracers of the ISM 570
  • Diffuse infrared emission 570
  • Pulsars and the Galactic magnetic field 574
  • Diffuse H[Alpha] radiation 576
  • Diffuse synchrotron and Gamma-radiation 577
  • Diffuse X-rays 579
• 9.4 The central disk 580
  • 21-cm observations 580
  • Observations in lines of CO and CS 586
  • A dynamical model of the central disk 588
• 9.5 The nucleus 594
• 9.6 Small-scale structure of the ISM 597
  • Molecular gas in the Galaxy 598
  • X from virial masses 601
  • X from Gamma-rays 601
  • X from A_v 602
• Problems 603

Components of the Milky Way

• 10.1 Gross Structure from Surface Photometry 609
  • The Galaxy at optical wavelengths 614
• 10.2 The bulge 616
  • Integrated surface photometry 616
  • Evidence for a bar from individual stars 619
  • Age and metallicity of the bulge 621
  • Bulge kinematics 622
• 10.3 Kinematics of stars near the Sun 624
  • The solar motion 624
  • Random velocities of stars 629
  • Vertex deviation 630
  • The Schwarzschild distribution 632
  • Star streams 634
  • Causes of vertex deviation 636
  • The Oort constants 637
  • Estimating the Oort constants 641
• 10.4 The structure of the stellar disk 643
  • Ages and metallicities of nearby stars 643
  • Correlations between abundances 643
  • Correlations between age and abundance 644
  • The old disk clusters 651
  • Star counts and the thick disk 651
  • The thick disk 654
  • The local mass density of the disk 656
  • Distribution of the youngest stars 664
• 10.5 The halo 666
  • The globular cluster system 666
  • Field halo stars 670
  • Kinematically selected samples 673
• 10.6 Galaxy models 678
  • The local circular speed 679
  • Mass models 680
  • Starcount models 682
  • Kinematic models 683
  • Dynamical models 683
• 10.7 Formation and evolution of the Milky Way 684
  • Formation scenarios 684
  • Models of the chemical evolution of the Milky Way 688
  • Chemical evolution of the halo 688
  • Pre-enrichment 688
• Problems 690

Stellar Kinematics in External Galaxies

• 11.1 Measuring the kinematics of external galaxies 694
  • Mean velocities and velocity dispersions 697
  • Analysis of line profiles 700
  • Position-velocity diagrams and data cubes 705
• 11.2 The stellar kinematics of elliptical galaxies 707
  • Large-scale properties 707
  • Major-axis kinematics 707
  • Detection of dark halos 712
  • Kinematic mapping 713
  • Core properties 716
  • Decoupled cores 716
  • Detection of central black holes 717
• 11.3 The stellar kinematics of disk galaxies 722
  • Bulge kinematics 723
  • Disk kinematics 724
  • Rotational motion 725
  • Random motions 727
• Problems 730

Appendices

1. Gravitational deflection of light 732
2. Important astronomical catalogs 736
3. Richardson-Lucy deconvolution 743
4. Useful numbers 744

References

Index