Résumé / Abstract Seminaire_IAP
« Groups and Clusters of Galaxies: Where Cosmology and Astrophysics Collide »

Arif Babul
Dept. Astronomy, Univ. Victoria (Victoria, Canada)

Clusters of galaxies are the largest, most massive gravitationally bound objects in the Universe. They are also the most recent of the cosmic objects to form. According to the currently accepted models of cosmic structure formation, the number density distribution of these systems is very sensitive to the parameters describing the large-scale geometry and the expansion history of the universe. For this reason, galaxy clusters are regarded as important cosmological probes. However, the precision with which the cosmological parameters can be determined depends critically on how well we understand why clusters manifest the observed properties that they do. Models of cosmic structure formation that come the closest in explaining these properties are those that invoke powerful energetic outflows from supermassive black holes at the centers of galaxies orbiting within the clusters. In this talk, I will briefly summarize why astrophysicists need objects roughly the size of the solar system to explain the evolution of structures many orders of magnitude larger. I will discuss observational evidence that lends credence to this picture and I will also highlight some outstanding crucial gaps in our understanding of the underlying physics.
vendredi 27 juin 2014 - 11:00
Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris
Page web du séminaire / Seminar's webpage