Résumé / Abstract Seminaire_IAP
« Structure Formation: à la recherche de paramètre perdu  »

Shant Baghram
Inst. Theoretical Physics Mathematics (IPM) (Téhéran, Iran)

The Cosmological observations like CMB and the Large scale structure(LSS) of the Universe are in favor of standard cosmological model known as LCDM, which describe the observations with 6 parameters. However the 95% of the Universe (Dark energy and Dark matter) is unknown and the physics of early Universe is not known yet. To address the problem of dark energy we use the Modified gravity f(R) theories as an alternative to the cosmological constant. These models can be distinguished from alternative models via the scale dependence growth of the structures. We show that matter growth rate measurements by galaxy surveys like SDSS and WiggleZ can constrained these models. Then we show that the non-Gaussian Anisotropic initial conditions from inflationary models, which are candidates to describe the CMB anomalies are also introducing a scale dependence in LSS through the bias parameter. This scale dependence can affect the measurements of matter growth rate due to redshift-space distortion, and it is degenerate with the signature of Modified gravity. Finally we argue that we need statistics in LSS observations and complementary observations like galaxy growth rate to break the degeneracy.
vendredi 30 août 2013 - 11:00
Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris
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