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Angular statistics of cosmological observables are hard to compute. The main difficulty is due to the presence of highly-oscillatory Bessel functions which need to be integrated over. In this paper, we provide a simple and fast method to…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-12 Valentin Assassi , Marko Simonović , Matias Zaldarriaga

Perturbation theory of large-scale structures of the Universe at next-to-leading order and next-to-next-to-leading order provides us with predictions of cosmological statistics at sub-percent level in the mildly non-linear regime. Its use…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-08 Ken Osato , Takahiro Nishimichi , Atsushi Taruya , Francis Bernardeau

A new method for estimating the power spectrum $C_l$ from cosmic microwave background (CMB) maps was recently presented by the author and applied to the 2 year COBE data. It was found that the spectral resolution $\Delta l$ for COBE could…

Astrophysics · Physics 2016-08-30 Max Tegmark

A common problem in cosmology is to integrate the product of two or more spherical Bessel functions (sBFs) with different configuration-space arguments against the power spectrum or its square, weighted by powers of wavenumber. Naively…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-03 Zachary Slepian , Yin Li , Marcel Schmittfull , Zvonimir Vlah

Forthcoming high-resolution observations of the Cosmic Microwave Background (CMB) radiation will generate datasets many orders of magnitude larger than have been obtained to date. The size and complexity of such datasets presents a very…

Astrophysics · Physics 2016-08-25 Julian Borrill

Clustering of the large scale structure provides complementary information to the measurements of the cosmic microwave background anisotropies through power spectrum and bispectrum of density perturbations. Extracting the bispectrum…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-19 Ji-Ping Dai , Licia Verde , Jun-Qing Xia

The spherical harmonic transform is a powerful tool in the analysis of spherical data sets, such as the cosmic microwave background data. In this work, we present a new scheme for the spherical harmonic transforms that supports both CPU and…

Instrumentation and Methods for Astrophysics · Physics 2022-11-18 Chi Tian , Siyu Li , Hao Liu

The new scheme of the energy measurement of the extremely high energy electron beam with the inverse Compton scattering between electrons and microwave photons requires the precise calculation of the interaction cross section of electrons…

Plasma Physics · Physics 2023-02-27 Meiyu Si , Shanhong Chen , Yongsheng Huang , Manqi Ruan , Guangyi Tang , Xiaofei Lan , Yuan Chen , Xinchou Lou

Spectroscopic redshift surveys offer great prospects for constraining the dark sector in cosmology. Future surveys will however be both deep and wide and will thus require an analysis in 3-dimensional spherical geometry. We review and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Andrina Nicola , Alexandre Refregier , Adam Amara , Aseem Paranjape

Angular power spectra are an important measure of the angular clustering of a given distribution. In Cosmology, they are applied to such vastly different observations as galaxy surveys that cover a fraction of the sky and the Cosmic…

Astrophysics · Physics 2007-11-15 Brett Hayes , Robert Brunner , Volodymyr Kindratenko

Several cosmological measurements have attained significant levels of maturity and accuracy over the last decade. Continuing this trend, future observations promise measurements of the statistics of the cosmic mass distribution at an…

Astrophysics · Physics 2008-11-26 Salman Habib , Katrin Heitmann , David Higdon , Charles Nakhleh , Brian Williams

The primordial power spectra of scalar and tensor perturbations during slow-roll inflation are usually calculated with the method of Bessel function approximation. For constant-roll or ultra slow-roll inflation, the method of Bessel…

General Relativity and Quantum Cosmology · Physics 2018-04-09 Zhu Yi , Yungui Gong

We describe an algorithm for the extraction of the angular power spectrum of an intensity field, such as the cosmic microwave background (CMB), from interferometer data. This new method, based on the gridding of interferometer visibilities…

The Cosmic Microwave Background Radiation (CMBR) holds information about almost all the fundamental cosmological parameters, and by performing a likelihood analysis of high precision CMBR fluctuation data, these parameters can be inferred.…

Astrophysics · Physics 2009-10-31 Steen Hannestad

Nonlinear effects are crucial in order to compute the cosmological matter power spectrum to the accuracy required by future generation surveys. Here, a new approach is presented, in which the power spectrum, the bispectrum and higher order…

Astrophysics · Physics 2009-11-13 Massimo Pietroni

Recent work in the literature has found a suppression or, instead, an enhancement of the Cosmic Microwave Background power spectrum in quantum gravity, although the effect is too small to be observed, in both cases. The present paper…

General Relativity and Quantum Cosmology · Physics 2015-06-18 Donato Bini , Giampiero Esposito

The Fisher information matrix of the cosmic microwave background (CMB) radiation power spectrum coefficients is a fundamental quantity that specifies the information content of a CMB experiment. In the most general case, its exact…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-30 Franz Elsner , Benjamin D. Wandelt

We apply several methods related to the WKB approximation to study cosmological perturbations during inflation, obtaining the full power spectra of scalar and tensor perturbations to first and to second order in the slow-roll parameters. We…

General Relativity and Quantum Cosmology · Physics 2007-05-28 Mattia Luzzi

The cosmic microwave background (CMB) power spectrum is a powerful cosmological probe as it entails almost all the statistical information of the CMB perturbations. Having access to only one sky, the CMB power spectrum measured by our…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-23 P. Paykari , J. L. Starck , M. J. Fadili

We present a new method for calculating CMB anisotropies in a non-flat Friedmann universe, relying on a very stable algorithm for the calculation of hyperspherical Bessel functions, that can be pushed to arbitrary precision levels. We also…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Julien Lesgourgues , Thomas Tram