Maria J. Pereira
Department of Astronomy, Columbia University, NY, USA

Abstract
A key assumption in cosmic shear and weak lensing measurements is that galaxies are randomly oriented in space. I will present observational evidence to the contrary over a wide range of scales, from the Local Group to the most massive clusters of galaxies, and argue that this is the result of a secular tidal interaction between substructure halos and the host potential. I will then present a set of N-body cosmological simulations that reinforce this hypothesis and I will conclude by discussing possible consequences of this gravitational effect for galaxy evolution.

2008 July 30, 10:24

IA/U.Porto
Centro de Astrofísica da Universidade do Porto (Auditorium)
Rua das Estrelas, 4150-762 Porto