Intrinsic alignments : Theoretical and numerical insights

Sandrine Codis (Canadian Institue for Theoretical Astrophysics)
Event Date and Time: 
Mon, 2016-04-04 15:30 - 16:30
Hennings 318
Local Contact: 
Jaymie Matthews
Intended Audience: 
In this talk, I will show how both dark matter and hydrodynamical simulations predict that the morphology of galaxies is correlated with the cosmic web. This large-scale coherence of galaxy shapes could possibly induce some non-negligible level of contamination for future cosmic shear experiments. Direct measurements of the alignment of the projected light distribution of galaxies seem to agree on a contamination at a level of a few per cent of the shear correlation functions, although the amplitude of the effect depends on the population of galaxies considered. Given this dependency and the inherently anisotropic nature of the large-scale structure and its complex imprint on the shapes and spins of galaxies, it is difficult to use dark matter-only simulations as the sole resource to predict and control intrinsic alignments. I will show how state-of-the-art hydrodynamical simulations like Horizon-AGN can be used to shed light on the level of intrinsic alignment we should expect for future weak lensing measurements. On the theoretical side, I will describe an analytical Lagrangian model that reproduces qualitatively the correlations between the intrinsic angular momentum of galaxies and the cosmic filaments, the key ingredient being to take into account the anisotropy of the cosmic web in the standard theory of spin acquisition by tidal torquing.
Website development by Checkmark Media. Designed by Armada.

a place of mind, The University of British Columbia

Faculty of Science
Department of Physics and Astronomy
6224 Agricultural Road
Vancouver, BC V6T 1Z1
Tel 604.822.3853
Fax 604.822.5324

Emergency Procedures | Accessibility | Contact UBC | © Copyright The University of British Columbia