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Using inpainting to construct accurate cut-sky CMB estimators

dc.creatorGruetjen, HF
dc.creatorFergusson, James Robert
dc.creatorLiguori, M
dc.creatorShellard, Edward Paul
dc.description.abstractThe direct evaluation of manifestly optimal, cut-sky cosmic microwave background (CMB) power spectrum and bispectrum estimators is numerically very costly, due to the presence of inverse-covariance filtering operations. This justifies the investigation of alternative approaches. In this work, we mostly focus on an inpainting algorithm that was introduced in recent CMB analyses to cure cut-sky suboptimalities of bispectrum estimators. First, we show that inpainting can equally be applied to the problem of unbiased estimation of power spectra. We then compare the performance of a novel inpainted CMB temperature power spectrum estimator to the popular apodized pseudo-C$_{l}$ (PCL) method and demonstrate, both numerically and with analytic arguments, that inpainted power spectrum estimates significantly outperform PCL estimates. Finally, we study the case of cut-sky bispectrum estimators, comparing the performance of three different approaches: inpainting, apodization and a novel low-l leaning scheme. Providing an analytic argument of why the local shape is typically most affected we mainly focus on local-type non-Gaussianity. Our results show that inpainting allows us to achieve optimality also for bispectrum estimation, but interestingly also demonstrate that appropriate apodization, in conjunction with low-l cleaning, can lead to comparable accuracy.
dc.publisherAmerican Physical Society
dc.publisherPhysical Review D - Particles, Fields, Gravitation and Cosmology
dc.titleUsing inpainting to construct accurate cut-sky CMB estimators

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