X-ray clusters of galaxies as tracers of structure in the Universe.
Clusters of galaxies are visible tracers of the network of matter in the Universe, marking the high-density regions where filaments of dark matter join together. When observed at X-ray wavelengths these clusters shine like cosmic lighthouses, as a consequence of the hot gas trapped within their gravitational potential wells. The X-ray emission is linked directly to the total mass of a cluster, and so can be used to investigate the mass distribution for a sizeable fraction of the Universe. The picture that has emerged from recent studies is remarkably consistent with the predictions for a low-density Universe dominated by cold dark matter.
Borgani
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INFN, Sezione di Trieste, c/o Dipartimento di Astronomia dell'Università, Via Tiepolo 11, I-34131, Trieste, Italy. borgani@ts.astro.it
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