Chapter 11

Highlights in modern observational

cosmology

Piero Rosati

European Southern Observatory, Garching b. Munchen, ̈

Germany

11.1 Synopsis

In this chapter, we focus on the fundamental methods of observational cosmology
and summarize some of the recent observational results which have deepened
our understanding of the structure and evolution of the universe. The chapter is
divided into three parts. In the first section, we briefly describe the Friedmann
world models, which constitute the theoretical framework, we define the main
observables and we illustrate some common applications. In the second section,
we describe how galaxy surveys (primarily in the optical band) are utilized to map
the structure and evolution of the universe over a large fraction of its age, focusing
on observational methodologies and some recent results. In the third section, we
describe how surveys of galaxy clusters can be used to constrain cosmological
models, and measure the fundamental cosmological parameters. Throughout the
chapter, we touchonlyon a few recent highlights in observational cosmology. We
refer the reader to fundamental textbooks, such as Longair (1998), Peebles (1993)
and Peacock (1999), for a complete overview of the theoretical and observational
framework.

11.2 The cosmological framework

This section gives a very brief summary of the basics of Friedmann–Robertson–
Walker (FRW) models; only the essentials formulae which are used throughout
the chapter and the definition of observable quantities which are often used in
cosmology are included.

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