Nominated as an outstanding thesis by Professor Robert Crittenden of the Institute of Cosmology and Gravitation in Portsmouth, and winner of the Michael Penston Prize for 2014 given by the Royal Astronomical Society for the best doctoral thesis in Astronomy or Astrophysics, this work aims to shed light on one of the most important probes of the early Universe: the bispectrum of the cosmic microwave background. The CMB bispectrum is a potential window on exciting new physics, as it is sensitive to the non-Gaussian features in the primordial fluctuations, the same fluctuations that evolved into today’s planets, stars and galaxies. However, this invaluable information is potentially screened, as not all of the observed non-Gaussianity is of primordial origin. Indeed, a bispectrum arises even for perfectly Gaussian initial conditions due to non-linear dynamics, such as CMB photons scattering off free electrons and propagating in an inhomogeneous Universe. Dr. Pettinari introduces the reader to this intrinsic bispectrum in a pedagogic way, building up from the standard model of cosmology and from cosmological perturbation theory, the tool cosmologists use to unravel the history of the cosmos. In doing so, he introduces SONG, a new and efficient code for solving the second-order Einstein and Boltzmann equations. Next, he moves on to answer the crucial question: is the intrinsic bispectrum going to screen the primordial signal in the CMB? Using SONG, he computes the intrinsic bispectrum and shows how its contamination leads to a small bias in the estimates of primordial non-Gaussianity, a great news for the prospect of using CMB data to probe primordial non-Gaussianity.

The series of texts composing this book is based on the lectures presented during the II José Plínio Baptista School of Cosmology, held in Pedra Azul (Espírito Santo, Brazil) between 9 and 14 March 2014. This II JBPCosmo has been entirely devoted to the problem of understanding theoretical and observational aspects of Cosmic Background Radiation (CMB).The CMB is one of the most important phenomena in Physics and a fundamental probe of our Universe when it was only 400,000 years old. It is an extraordinary laboratory where we can learn from particle physics to cosmology; its discovery in 1965 has been a landmark event in the history of physics.The observations of the anisotropy of the cosmic microwave background radiation through the satellites COBE, WMAP and Planck provided a huge amount of data which are being analyzed in order to discover important informations regarding the composition of our universe and the process of structure formation.

Explanations of the cosmic microwave background prompt this unique case study of theory building in modern science.

Modern cosmology, packaged for use on physics courses.

In the last fifteen years, various areas of high energy physics, astrophysics and theoretical physics have converged on the study of cosmology so that any graduate student in these disciplines today needs a reasonably self-contained introduction to the Cosmic Microwave Background (CMB). This book presents the essential theoretical tools necessary to acquire a modern working knowledge of CMB physics. The style of the book, falling somewhere between a monograph and a set of lecture notes, is pedagogical and the author uses the typical approach of theoretical physics to explain the main problems in detail, touching on the main assumptions and derivations of a fascinating subject.

This book is the result of a Meeting held in L'Aquila (Italy) from the 19th to the 23rd of June 1989. The aim of the Meeting was to gather together the people actively working on the Cosmic Microwave Background radiation, both from an experimental and from a theoretical point of view. In view of the intensive current activity in this field, including ongoing (COBE) and forthcoming (RELIC II, ISO, AELITA, etc. ) space missions, a meeting fully dedicated to this important topic was timely. The meeting also celebrated the 25th anniversary of the Microwave Background discovery made in 1964 by the Nobel Prize winners A. Penzias and R. Wilson. We greatly regret that we were not able to have them at the Meeting. There is of course another person whose absence we regret, namely R. H. Dicke, who motivated a generation of experimentalists and theoreticians to open and study this new field of research. As organizers of the Meeting, we would like to express our gratitude to the people who contributed to its success. We want to thank the members of the Scientific Organizing Committee for their assistance, suggestions and encouragement, the invited speakers for their excellent presentations, and the chairmen for their help in handling the various Sessions. We would like to thank P. Palazzi for her help in secretarial work, dr. L.

Ever since its infancy, humankind has been seeking answers to some very basic and profound questions. Did the Universe begin? If it did, how old is it, and where did it come from? What is its shape? What is it made of? Fascinating myths and brilliant in- itions attempting to solve such enigmas can be found all through the history of human thought. Every culture has its own legends, itsownworldcreationtales,itsphilosophicalspeculations,itsre- gious beliefs. Modern science, however, cannot content itself with fanciful explanations, no matter how suggestive they are. No- days, our theories about the Universe, built upon rational ded- tion, have to survive the hard test of experiment and observation. Cosmology, the science which studies the origin and evo- tion of the Universe, had to overcome enormous dif?culties before it could achieve the same level of dignity as other physical dis- plines. At ?rst, it had no serious physical model and mathematical tools that could be used to address the complexity of the problems it had to face. Then, it suffered from a chronic lack of experim- tal data, which made it almost impossible to test the theoretical speculations. Given this situation, answering rigorously the many questions on the nature of the Universe seemed nothing more than a delusion. Today, however, things have changed. We live in the golden age of cosmology: an exciting moment, when, for the ?rst time, we are able to scienti?cally understand our Universe.