Application of XFaster power spectrum and likelihood estimator to Planck

Abstract

We develop the XFASTER cosmic microwave background (CMB) temperature and polarization anisotropy power spectrum and likelihood technique for the Planck CMB satellite mission. We give an overview of this estimator and its current implementation, and present the results of applying this algorithm to simulated Planck data. We show that it can accurately extract the power spectrum of Planck data for the high-l multipoles range. We compare the XFASTER approximation for the likelihood to other high-l likelihood approximations such as Gaussian and Offset Lognormal and a low-l pixel-based likelihood. We showthat theXFASTER likelihood is not only accurate at high l, but also performs well at moderately low multipoles. We also present results for cosmological parameter Markov chain Monte Carlo estimation with the XFASTER likelihood. As long as the low-l polarization and temperature power are properly accounted for, e.g. by adding an adequate low-l likelihood ingredient, the input parameters are recovered to a high level of accuracy.