Accueil > Séminaires d’Astrophysique > Automne 2005 > The Cosmological Mean Density and its Local Variations Probed by Peculiar Velocities

 

The Cosmological Mean Density and its Local Variations Probed by Peculiar Velocities

Roya Mohayaee (Institut d’Astrophysique de Paris)

Par Stephane Charpinet - 27/08/2007

 

Séminaires d’Astrophysique

de l’Observatoire Midi-Pyrénées


Séminaire de 

Roya MOHAYAEE

(Institut d’Astrophysique de Paris)


Jeudi 27 Octobre 2005 à 11h

OMP - Salle Coriolis


The Cosmological Mean Density and its Local Variations Probed by Peculiar Velocities


Peculiar velocities throughout the region of the local supercluster can be reconstructed by orbit-retracing methods. The requirement of the optimal correlation between the radial components of reconstructed velocities and the observed peculiar velocities derived from our extensive new catalog of distances puts stringent constraints on the values of the cosmological parameters. I shall show you that our constraints intersect those from studies of microwave background fluctuations and statistical properties of galaxy clustering : the ensemble of constraints are consistent with Omega_m=0.22 +- 0.02.
 
While motions throughout the Local Supercluster provide a measure of the mean ratio of mass to light, there can be large local fluctuations. Our reconstruction of the infall velocities in the immediate vicinity of the Virgo Cluster shows that there is a mass-to-light anomaly of a factor of 3 to 6 between groups in the general field environment and the heavily populated Virgo Cluster.

 

 

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Laboratoire Astrophysique de Toulouse - Tarbes (UMR5572)

CNRS (Midi-Pyrénées)

Univ. Paul Sabatier

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