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Journal-club Univers / Journal-club Universe

« Perturbation theory challenge for cosmological parameters estimation »

Ken Osato
Institut d'Astrophysique de Paris (Paris, France)

We study the accuracy with which cosmological parameters can be determined from real space power spectrum of matter density contrast at weakly nonlinear scales using analytical approaches. From power spectra measured in N-body simulations and using Markov chain Monte-Carlo technique, the best fitting cosmological input parameters are determined with several analytical methods as a theoretical template, such as the standard perturbation theory, the regularized perturbation theory, and the effective field theory. We show that at redshift 1, all two-loop level calculations can fit the measured power spectrum down to scales k ~ 0.2 h Mpc^-1 and cosmological parameters are successfully estimated in an unbiased way. Introducing the Figure of bias and Figure of merit parameter, we determine the validity range of those models and then evaluate their relative performances. We also discuss the ongoing work on the similar challenge for redshift space power spectrum with fast calculations.
mardi 16 juin 2020 - 10:30
Webinaire, Institut d'Astrophysique
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