The Structure and Evolution of Galaxies

The Structure and Evolution of Galaxies is a concise introduction to this fascinating subject providing the reader with the fundamentals in a clear and accessible style. This user-friendly text assumes some prerequisite knowledge of astronomy, with the necessary mathematics kept to a minimum. Beginning with an introduction to the existence of our own external galaxies, the book moves on to discuss how perceptions of galaxy development have changed over time. The three categories of galaxies are then discussed with later chapters considering their formation and evolution. The book concludes with an overview of both current developments in the field and considers the direction of future research.  Clear and accessible introduction to this dynamic subject Introduces definitions of key terms and puts them in context Includes current research and future developments in the field Appendix of basic definitions to clarify key concepts An invaluable text for students of astronomy and physics

Table of Contents:
Preface ix 1 Galaxies in the universe 1 1.1 Introduction 1 1.2 A brief history of galaxies 2 1.3 Distance measurements 5 1.4 Redshifts, distances and dynamics 9 1.5 Expansion of the universe 10 1.6 Hubble’s constant and the distance scale 12 1.7 The observable universe 16 2 A galaxy menagerie 19 2.1 Morphological types 19 2.2 Luminosities and sizes 21 2.3 Surface brightness 24 2.4 Surface brightness profiles 26 2.5 Apparent sizes 28 2.6 The luminosity function 30 2.7 Redshift surveys 33 2.7.1 Galactic extinction 33 2.7.2 k-corrections 36 2.7.3 Volume densities 36 2.8 Galaxies at all wavelengths 39 2.9 Active galaxies 41 2.10 Galaxy environments 41 3 Elliptical and lenticular galaxies 45 3.1 Numbers 45 3.2 Surface brightness laws 47 3.3 Shapes 52 3.4 Stellar populations 55 3.4.1 Stellar lifetimes 57 3.4.2 Stellar population evolution 58 3.4.3 Surface brightness fluctuations 61 3.5 Metallicity 61 3.6 Globular clusters 64 3.7 Hot gas 64 3.8 Dynamics 66 3.8.1 Rotation 67 3.8.2 The virial theorem 69 3.9 The Faber–Jackson relation and the fundamental plane 71 3.9.1 Peculiar velocities 72 3.9.2 Mass-to-light ratios 73 3.10 Mergers 75 3.10.1 Gravitational interactions 78 3.10.2 Timescales 81 3.11 Elliptical galaxy masses 83 3.12 Massive black holes 86 4 Spiral galaxies 87 4.1 Shapes and sizes 87 4.1.1 Spiral arms 89 4.1.2 Surface brightnesses 91 4.1.3 Numbers 94 4.2 Vertical structure 95 4.2.1 Thin and thick discs 96 4.2.2 Surface densities 97 4.3 Rotation 98 4.3.1 Oort’s constants 100 4.3.2 Epicyclic motions 102 4.3.3 The velocity ellipsoid 105 4.4 Stellar populations 105 4.4.1 Colours 108 4.4.2 The initial mass function 109 4.5 The interstellar medium 110 4.5.1 HI 111 4.5.2 Other constituents of the ISM 113 4.6 Neutral gas 114 4.6.1 HI observations 116 4.6.2 The HI and HII distributions 118 4.7 Ionised gas 120 4.8 ISM structure 122 4.8.1 Magnetic fields 123 4.8.2 The radio LF 125 4.8.3 Cosmic rays 125 4.9 Dust 126 4.9.1 Reddening 128 4.9.2 Optical depths 129 4.10 Spiral structure 131 4.10.1 Density waves 132 4.10.2 Bars 134 4.11 Star formation 134 4.11.1 The Jeans mass 135 4.12 Global star formation 137 4.12.1 Emission lines 137 4.12.2 Other star formation indicators 138 4.12.3 Densities and timescales 141 4.13 Chemical evolution 144 4.13.1 Closed box models 144 4.13.2 Gas flows 147 4.13.3 Radial gradients 150 4.14 Rotation of the gas 151 4.14.1 Rotation of gas in the Galaxy 154 4.15 The Tully–Fisher relation 155 4.16 The Galactic halo 158 4.17 The Galactic Centre 160 5 Irregulars, dwarfs and LSBGs 165 5.1 Local Group members 166 5.2 Irregulars 167 5.2.1 Metallicities 169 5.3 Early type dwarfs 172 5.3.1 Galactic winds 174 5.4 Star formation histories 176 5.5 Interactions 177 5.6 Interconnections 181 5.7 Low surface brightness discs 182 5.8 Numbers and selection effects 183 5.9 Dwarf galaxies in the past 186 6 Active galaxies 189 6.1 The discovery of AGN 189 6.2 AGN structure 194 6.2.1 Accretion discs 195 6.2.2 Broad line clouds and the molecular torus 196 6.2.3 Timescales 198 6.2.4 LINERs 199 6.3 Radio galaxies 200 6.4 Synchrotron emission 203 6.4.1 Energy loss rates 205 6.4.2 Acceleration processes 207 6.4.3 Energy densities 209 6.5 Jets and superluminal motion 211 6.6 Unification 212 7 Clusters and clustering 215 7.1 The distribution of galaxies 215 7.2 Rich clusters 216 7.3 Cluster masses 218 7.3.1 Virial masses 219 7.3.2 Gravitational lensing 221 7.3.3 X-ray clusters 225 7.3.4 X-ray luminosities 226 7.4 Cluster searches 227 7.5 Galaxy groups 229 7.6 Intergalactic matter 232 7.7 Large-scale structure 234 7.8 Clustering statistics 237 7.8.1 Correlation functions 237 7.8.2 Limber’s formula 239 7.8.3 Clustering lengths 241 7.8.4 The power spectrum 242 7.9 Velocities 243 8 Galaxy evolution 247 8.1 Looking back 247 8.2 Redshift and distance 248 8.2.1 Observable distances 250 8.3 Cosmological models 252 8.3.1 The density parameter 253 8.3.2 The cosmic scale factor 255 8.3.3 Distance revisited 258 8.4 The Hubble diagram 259 8.4.1 Evolutionary corrections 260 8.5 Galaxy colours, photometric redshifts and LBGs 263 8.5.1 Drop-outs 265 8.5.2 FIR and sub-millimetre sources 265 8.6 Number counts 266 8.6.1 Evolution again 267 8.6.2 Faint blue galaxies 270 8.6.3 Radio source counts 270 8.6.4 Quasars 271 8.7 The night sky brightness 272 8.7.1 Metal production 274 8.7.2 QSO absorption lines 274 8.8 The star formation history of the universe 276 8.8.1 Star formation models 277 8.8.2 Star formation at high z 279 8.9 Reionisation and the first stars 281 8.10 Galaxy formation theory 281 8.11 Further developments 284 Appendix: The magnitude system 285 Figure credits 289 Bibliography 295 Index 299

About the Author :
Steve Phillipps is the author of The Structure and Evolution of Galaxies, published by Wiley.