Istituto di Astrofisica Spaziale e Fisica cosmica Milano
Clusters of galaxies are the largest and most massive, gravitational bound structures in the Universe.
Lying at the nodes of the cosmic web filaments in the present highly structured Universe, clusters of galaxies are at crossroads of cosmology and astrophysics: on one side they trace cosmic evolution providing information on structure formation, and are powerful tools to test the underlying cosmological models; on the other side they are unique astrophysical laboratories, ideal for the study of plasma physics, thermal and non-thermal processes, turbulence, magnetic fields, dark matter, etc.
Clusters are complex structures. They typically contain from tens to thousands galaxies. Nonetheless only few percent of their total mass is in the form of optical galaxies. Dark matter is the dominant (about 80%) component of clusters. About 15-20% of the total mass consists of diffuse, hot, metal-enriched, X-ray emitting plasma permeating the space between the galaxies: the intracluster medium (ICM).
Our group is active in exploiting data from various X-ray satellites (ROSAT, Beppo-SAX and XMM-Newton, Chandra, NuStar) to inspect in details clusters’ physics and evolution, aided also by observations at other wavelengths: radio (e.g. LOFAR), millimeter (through the SZ effect, e.g. Planck) and optical. We are involved in several projects like XCOP, XMM Cluster Heritage Project, XXL.