Séminaire / Seminar GReCO |
| « Weak lensing in scalar-tensor theories of gravity » |
|
Carlo Schimd |
| Scalar-tensor (ST) theories of gravitation are the best motivated alternative to general relativity (GR), arising in every high-energy theory attempting to unify all the fundamental interactions including gravity. Furthermore, accomodating an arbitrary number of scalar fields, ST theories yield to cosmological scenarios with a dynamical realization of the dark energy. Solar-System experiments and binary-pulsars observations are compatible with very small departures from GR on the local universe. On cosmological scales, big-bang nucleosynthesis and cosmic microwave background (CMB) observables can admit larger deviations from the predictions of GR. Weak lensing could provide a tool to test ST theories of gravity on intermediate scales. I will present recent results obtained using a CMB-lensing code, originally developed to study the effects of ST theories on CMB observables, now implemented to compute the weak lensing observables, namely the convergence power spectrum and some 2-points statistics. Two classes of ST models have been investigated: the simplest one, a quadratic non-minimal coupling, and the more interesting class involving an attraction mechanism toward GR. In the latter case, weak lensing observables can point deviations from GR of order 10%. |
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jeudi 16 décembre 2004 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |