Résumé / Abstract Seminaire_GReCO
SÉMINAIRE DU GRECO

"Cosmological parameters in models with correlated isocurvature perturbations"

Vesa Muhonen
Helsinki Inst. Physics, Univ. Helsinki (Helsinki, Finlande)

We use cosmic microwave background (CMB) and large-scale structure data to constrain cosmological models where the primordial perturbations have both an adiabatic and a cold dark matter (CDM) isocurvature component. A likelihood analysis with 11 independent parameters gives the upper limit of 7,5% for the non-adiabatic contribution to the CMB temperature variance. Of the standard cosmological parameters, determination of the CDM density and the sound horizon angle (or the Hubble constant) are affected most by a possible presence of a correlated isocurvature contribution. The physical baryon density nearly retains its adiabatic value. Finally, I will discuss the MCMC method and the effect of choosing the pivot scale for the definition of amplitude parameters of the primordial spectra.

jeudi 24 février 2005 - 11:00
Salle des séminaires Évry Schatzman,
Institut d'Astrophysique de Paris

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