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The Evolution of X-ray Clusters of Galaxies
Piero Rosati,1,3
Stefano Borgani,2
and Colin Norman3,4
1 European
Southern Observatory, D-85748 Garching bei München, Germany;
email: prosati@eso.org
2 Dipartimento di Astronomia dell'Università di
Trieste, via Tiepolo 11, I-34131 Trieste, Italy;
email: borgani@ts.astro.it
3 Department
of Physics and Astronomy,
The Johns Hopkins
University, Baltimore, Maryland 21218;
email: norman@stsci.edu
4 Space Telescope Science
Institute, Baltimore, Maryland 21218
Abstract. Considerable progress has been made over the last
decade in the study of the evolutionary trends of the population of
galaxy clusters in
the Universe. In this review we focus on observations in the X-ray
band. X-ray surveys with the ROSAT satellite, supplemented by
follow-up studies with ASCA and Beppo-SAX, have allowed
an assessment of the evolution of the space density of clusters out
to z 
1, and
the evolution of the physical properties of the
intra-cluster medium out to z
0.5.
With the advent of Chandra and Newton-XMM, and their
unprecedented sensitivity and angular resolution, these studies have
been extended beyond redshift unity and have revealed the complexity
of the thermodynamical structure of clusters. The properties of the
intra-cluster gas are significantly affected by non-gravitational
processes including star formation and Active Galactic Nucleus
(AGN) activity. Convincing
evidence has emerged for modest evolution of both the bulk of the
X-ray cluster population and their thermodynamical properties since
redshift unity. Such an observational scenario is consistent with
hierarchical models of structure formation in a flat low density
universe with
m
0.3 and
8
0.7 - 0.8 for the
normalization of the power spectrum. Basic methodologies for
construction of X-ray-selected cluster samples are reviewed and
implications of cluster evolution for cosmological models are discussed.
Table of Contents
INTRODUCTION
- PHYSICAL PROPERTIES OF GALAXY CLUSTERS
- X-ray properties of clusters
- Cooling in the Intra Cluster Medium
- OBSERVATIONAL FRAMEWORK
- Optically-based Cluster Surveys
- X-ray Cluster Surveys
- Strategies and Selection Functions for X-ray
Surveys
- Other methods
- THE SPACE DENSITY OF X-RAY CLUSTERS
- Local Cluster Number Density
- The Cluster Abundance at Higher Redshifts and Its
Evolution
- Distant X-ray Clusters: the Latest View from
Chandra
- COSMOLOGY WITH X-RAY CLUSTERS
- The cosmological mass function
- Deriving from cluster evolution
- OUTLOOK AND FUTURE WORK
- REFERENCES
