An Introduction to Distance Measurement in Astronomy

Preface xi 1 The Importance of Astrophysical Distance Measurements 1 1.1 The Distance to the Galactic Centre 2 1.1.1 Early Determinations of R0 3 1.1.2 Modern Results 6 1.2 The Distance to the Large Magellanic Cloud 11 1.3 Benchmarks Beyond the Magellanic Clouds: the 3D Universe on Large(r) Scales 15 Bibliography 22 2 The Solar Neighbourhood 31 2.1 Geometric Parallax Measurements 31 2.1.1 Trigonometric Parallax 31 2.1.2 Astrometric Advances: Space-Based Missions and Interferometry 33 2.1.3 Secular and Statistical Parallaxes: Moving Groups Method 39 2.2 Dynamical Parallax 42 2.2.1 Mass Luminosity Relations 46 2.3 Spectroscopic and Photometric Parallaxes 50 Bibliography 55 3 From the MilkyWay to the Local Group 63 3.1 Basic Stellar Physics as the Key to Understanding Distance Measurements to Local Group Galaxies 63 3.1.1 Stellar Evolution Through the Hertzsprung Russell Diagram 63 3.1.2 From Two to Multiple Stellar Populations 68 3.2 Open and Globular Cluster Hertzsprung Russell Diagrams 70 3.2.1 Main-Sequence and Subdwarf Fitting 70 3.2.2 Red Clump Stars 72 3.2.3 The (Zero-Age) Horizontal Branch Level 74 3.3 Giants and Supergiants as Standard Candles 76 3.3.1 The Tip of the Red Giant Branch 76 3.3.2 The Red Giant Branch Bump 78 3.3.3 Supergiants as Standard Candles 80 3.4 White Dwarf Sequences 83 3.5 Period Density Relations 84 3.5.1 The Baade Wesselink Method 85 3.5.2 Classical Cepheid Variables 87 3.5.3 Mira Variables 90 3.5.4 W Virginis and Other Population II Cepheids 93 3.5.5 RR Lyrae Stars 95 3.5.6 Dwarf and Anomalous Cepheids 97 3.6 Novae as Standard Candles 98 3.7 Geometric Methods 100 3.7.1 Planetary Nebula Expansion Parallaxes 101 3.7.2 Supernova Light Echoes 102 3.7.3 Eclipsing Binary Stars 106 3.7.4 Maser-Based Distance Determinations 108 3.8 Pulsars: Distance Measurements Outside the Classical Wavelength Range 110 Bibliography 114 4 Reaching Virgo Cluster Distances and Beyond 135 4.1 The Hubble Space Telescope Key Project 135 4.2 Surface Brightness Fluctuations 136 4.3 The Globular Cluster Luminosity Function 140 4.3.1 Elliptical Versus Spiral Galaxy GCLFs 141 4.3.2 The Stellar Population Mix 144 4.3.3 GCLF and GCMF Universality Through Dynamical Evolution 144 4.4 The Planetary Nebulae Luminosity Function 148 4.4.1 Applicability 149 4.4.2 Physical Basis 150 4.5 The Tully Fisher Relation 151 4.5.1 Wavelength Dependence 152 4.5.2 The Scatter in the Tully Fisher Relation 154 4.6 Distance Indicators Specific to Elliptical Galaxies 156 4.7 The Colour Magnitude Relation 161 4.8 Hii Regions as Distance Indicators? 164 Bibliography 165 5 From Nearby Galaxy Clusters to Cosmological Distances 175 5.1 Cosmological Redshifts 175 5.1.1 Determination of the Current Expansion Rate of the Universe 175 5.1.2 Redshift Surveys and Peculiar Velocities 176 5.1.3 The Prevailing Cosmological Model 179 5.2 Supernovae as Beacons 186 5.2.1 Type Ia Supernovae 188 5.2.2 Type II-P Supernovae 197 5.2.3 A Link to Gamma-Ray Bursts as Standard Candles? 207 5.3 Indirect Techniques to Measure H0 210 5.3.1 Gravitational Lensing: Time Delays 210 5.3.2 The Sunyaev Zel dovich Effect 215 5.3.3 Anisotropies in the Cosmic Microwave Background 222 5.3.4 The Drive for Improved Accuracy 225 Bibliography 227 6 Systematic Uncertainties and Common Pitfalls 243 6.1 Common Biases 244 6.1.1 Extinction: Spatial Distribution and Wavelength Dependence 244 6.1.2 Parallaxes: Lutz Kelker Bias 246 6.1.3 Malmquist Bias 251 6.2 High Versus Low Values of the Hubble Constant: Science or Philosophy? 255 Bibliography 259 7 Promises and Prospects 267 7.1 The Way Forward: Where Are Significant Gains Achievable? 267 7.2 The Pleiades Distance Controversy 270 7.3 X-Ray Scattering Haloes 273 7.4 Standard Sirens: Listening to Gravitational Waves 276 7.5 Three-Dimensional Mapping of Redshifted Neutral Hydrogen 280 7.6 The Present-Day Distance Ladder 283 Bibliography 285 Glossary 293 Figure Credits 305 Index 309