Résumé / Abstract Seminaire_IAP
« Measuring masses: from galaxy clusters down to galaxies »

Henk Hoekstra
Leiden Obs. (Leiden, Pays-Bas)

The mass of an object is a fundamental observable. Unfortunately, on scales of galaxies and larger most of the mass is invisible. Dynamical studies have provided some of the earliest evidence for the existence of dark matter, but the tracers are typically confined to small radii, or may not have reached equilibrium. Numerical simulations can help understand and quantify the shortcomings of such methods, but how can one make sure the simulations are correct? In this talk I will discuss how weak gravitational lensing can be used to make the link between easily observed quantities and the underlying dark matter distribution. For instance, weak gravitational lensing studies provide a unique way to study the shapes of dark matter halos and their extent. In the case of galaxy clusters, we can now study large enough samples to provide an important link between various observational probes and simulations. This is a critical area for studies of cosmological parameters that use the number density of clusters.
vendredi 4 mars 2011 - 11:00
Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris
Page web du séminaire / Seminar's webpage