36 research outputs found
Radio Properties of REX BL Lacs and Galaxies
Detailed VLA observations have been gathered for a number of sources classified as either BL Lacs or galaxies, derived from the REX survey. We focus in particular on the sources identified by us, for which we have in hand homogeneous optical data, to study in more detail than allowed by the NVSS the radio properties of these sources in the framework of AGN unified models
Cosmological parameters from Galaxy Clusters: an Introduction
This lecture is an introduction to cosmological tests with clusters of
galaxies. Here I do not intend to provide a complete review of the subject, but
rather to describe the basic procedures to set up the fitting machinery to
constrain cosmological parameters from clusters, and to show how to handle data
with a critical insight. I will focus mainly on the properties of X-ray
clusters of galaxies, showing their success as cosmological tools, to end up
discussing the complex thermodynamics of the diffuse intracluster medium and
its impact on the cosmological tests.Comment: 32 pages, 16 figures, conference proceedings for the 3rd Aegean
Summer School, Chios, 26 September - 1 October, 200
Cosmology with clusters of galaxies
In this Chapter I review the role that galaxy clusters play as tools to
constrain cosmological parameters. I will concentrate mostly on the application
of the mass function of galaxy clusters, while other methods, such as that
based on the baryon fraction, are covered by other Chapters of the book. Since
most of the cosmological applications of galaxy clusters rely on precise
measurements of their masses, a substantial part of my Lectures concentrates on
the different methods that have been applied so far to weight galaxy clusters.
I provide in Section 2 a short introduction to the basics of cosmic structure
formation. In Section 3 I describe the Press--Schechter (PS) formalism to
derive the cosmological mass function, then discussing extensions of the PS
approach and the most recent calibrations from N--body simulations. In Section
4 I review the methods to build samples of galaxy clusters at different
wavelengths. Section 5 is devoted to the discussion of different methods to
derive cluster masses. In Section 6 I describe the cosmological constraints,
which have been obtained so far by tracing the cluster mass function with a
variety of methods. Finally, I describe in Section 7 the future perspectives
for cosmology with galaxy clusters and the challenges for clusters to keep
playing an important role in the era of precision cosmology.Comment: 49 pages, 19 figures, Lectures for 2005 Guillermo Haro Summer School
on Clusters, to appear in "Lecture notes in Physics" (Springer