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arXiv · 1807.09540

Beyond the traditional Line-of-Sight approach of cosmological angular statistics

Nils Schöneberg·Marko Simonović·Julien Lesgourgues·Matias Zaldarriaga
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Abstract

We present a new efficient method to compute the angular power spectra of large-scale structure observables that circumvents the numerical integration over Bessel functions, expanding on a recently proposed algorithm based on FFTlog. This new approach has better convergence properties. The method is explicitly implemented in the CLASS code for the case of number count $C_\ell$'s (including redshift-space distortions, weak lensing, and all other relativistic corrections) and cosmic shear $C_\ell$'s. In both cases our approach speeds up the calculation of the exact $C_\ell$'s (without the Limber approximation) by a factor of order 400 at a fixed precision target of 0.1%.

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Nils Schöneberg, Marko Simonović, Julien Lesgourgues, Matias Zaldarriaga. 2018-08-08. Beyond the traditional Line-of-Sight approach of cosmological angular statistics. https://doi.org/10.1088/1475-7516%2F2018%2F10%2F047

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