Cosmology

Since the first French edition of the book emphasized rather the solid facts of Cosmology than the detailed discussions of controversial results, relatively few revisions were necessary for the English edition. They were made early in 1979 and affected about 5% of the text. The main revisions referred to the distance scale, the dlstribution of galaxies, the X-ray observations of clusters, the cosmic time evolution of quasars and radiogalaxies and the 3 K radiation. A new short bibliography presents the recent articles and the latest proceedings of Symposia; from these the reader can easily trace a more complete list of refer­ ences. I am happy to thank Professor Beiglbock for suggestions he made to improve Part lIon Spaces of Constant Curvature, and Drs. S. and J. Mitton for translating the manuscript into English. I also thank with pleasure Marie-Ange Sevin for correcting the final version. J. Heidmann March 1980, Meudon, France Preface The aim of this book is to present the fundamentals of cosmology.

This is a textbook intended for students and researchers who wish to under­ stand the physics of standard "big bang" cosmology and how it is used to interpret the most recent observations. It is based on courses given over the last seven years to beginning graduate students at the University of Paris and to advanced undergraduates at l'Ecole Poly technique. Since the great major­ ity of these students did not intend to become professional cosmologists, I have emphasized subjects that should be of general interest. Progress in observations over the last ten years has been truly astounding and a new textbook might be justified simply to report on recent break­ throughs. The traditional successes of modern cosmology are well-known. Among these are the dynamical understanding of the universal expansion, the prediction of the cosmic microwave background radiation, and the calculation of the abundances of the light elements. To these we can add new observa­ tions that suggest that we are beginning the era of "precision cosmology.