Résumé / Abstract Seminaire_IAP
« Cosmic shear as a probe of precision cosmology »

Martin Kilbinger

Cosmic shear, the weak gravitational lensing of distant galaxies by the large-scale structure of the Universe, is an important powerful tool to study both the dark matter growth of structure as well as the expansion history of the Universe. It is considered to be one of the most promising methods to constrain dark energy.
After a brief introduction to the principles of cosmic shear, I will present our most recent cosmic shear results from the CFHTLS-Wide survey. We measured the very weak lensing signal out to four degrees, reaching well into the linear regime. It allowed us to constrain cosmological parameters free from uncertainties related to small-scale, non-linear physics. This signifies a big step towards future all-sky cosmic shear surveys.
I will then discuss sources of contamination to the weak lensing signal stemming from intrinsic galaxy alignment and galaxy clustering. These effects have to be understood and corrected for if cosmic shear is to be used as a precision cosmology probe. Vice versa, if the lensing and the intrinsic signal can be measured independently we can learn about galaxy formation and biasing. Finally, I will give an outlook of the expected constraints on dark energy if our CFHTLS-Wide lensing results are combined with Supernovae Ia (SNLS) and CMB (WMAP3).
vendredi 21 décembre 2007 - 11:00
Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris
Page web du séminaire / Seminar's webpage