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Related papers: The Cosmic Linear Anisotropy Solving System (CLASS…

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Boltzmann codes are used extensively by several groups for constraining cosmological parameters with Cosmic Microwave Background and Large Scale Structure data. This activity is computationally expensive, since a typical project requires…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Diego Blas , Julien Lesgourgues , Thomas Tram

We present a new flexible, fast and accurate way to implement massive neutrinos, warm dark matter and any other non-cold dark matter relics in Boltzmann codes. For whatever analytical or numerical form of the phase-space distribution…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-14 Julien Lesgourgues , Thomas Tram

By confronting the two independent Boltzmann codes CLASS and CAMB, we establish that for concordance cosmology and for a given recombination history, lensed CMB and matter power spectra can be computed by current codes with an accuracy of…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Julien Lesgourgues

In this work we present 21cmFirstCLASS, a modified version of 21cmFAST, the most popular code in the literature for computing the anisotropies of the 21-cm signal. Our code uses the public cosmic microwave background (CMB) Boltzmann code…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-29 Jordan Flitter , Ely D. Kovetz

Cosmological Boltzmann codes are often used by researchers for calculating the CMB angular power spectra from different theoretical models, for cosmological parameter estimation, etc. Therefore, the accuracy of a Boltzmann code is of utmost…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-09 Santanu Das , Anh Phan

We present a new open-source code that calculates one-loop power auto- and cross-power spectra for matter fields and biased tracers in real and redshift space. These spectra incorporate all ingredients required for a direct application to…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 Anton Chudaykin , Mikhail M. Ivanov , Oliver H. E. Philcox , Marko Simonović

We compare three independent, cosmological linear perturbation theory codes to asses the level of agreement between them and to improve upon it by investigating the sources of discrepancy. By eliminating the major sources of numerical…

Astrophysics · Physics 2008-11-26 U. Seljak , N. Sugiyama , M. White , M. Zaldarriaga

The Cosmology Large Angular Scale Surveyor (CLASS) is an experiment to measure the signature of a gravita-tional-wave background from inflation in the polarization of the cosmic microwave background (CMB). CLASS is a multi-frequency array…

Large scale structure of the Universe becomes a leading source of precision cosmological information. We present two particular tools that can be used in cosmological analyses of the redshift space galaxy clustering data: a new open-source…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-15 A. Chudaykin

We present some accurate and efficient computations of large scale structure observables, obtained with a modified version of the CLASS code which is made publicly available. This code includes all relativistic corrections and computes both…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-04 Enea Di Dio , Francesco Montanari , Julien Lesgourgues , Ruth Durrer

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

The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from inflation and the optical depth to reionization through a measurement of the polarized cosmic…

Cosmological parameter estimation from forthcoming experiments promise to reach much greater precision than current constraints. As statistical errors shrink, the required control over systematic errors increases. Therefore, models or…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 José Luis Bernal , Nicola Bellomo , Alvise Raccanelli , Licia Verde

The package CosmoLib is a combination of a cosmological Boltzmann code and a simulation toolkit to forecast the constraints on cosmological parameters from future observations. In this paper we describe the released linear-order part of the…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-12 Zhiqi Huang

The power spectrum is the most commonly applied summary statistics to extract cosmological information from the observed three-dimensional distribution of galaxies in spectroscopic surveys. We present CLASS-OneLoop, a new numerical tool,…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-28 Dennis Linde , Azadeh Moradinezhad Dizgah , Christian Radermacher , Santiago Casas , Julien Lesgourgues

These notes are very much work-in-progress and simply intended to showcase, in various degrees of details (and rigour), some of the cosmology calculations that class_sz can do. We describe the class_sz code in C, Python and Jax. Based on…

The cosmological principle is a cornerstone of the standard cosmological model. However, recent observations suggest potential deviations from this assumption, hinting at a small anisotropic expansion. Such an expansion can arise from…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-23 Jose L. Palacios-Córdoba , J. Bayron Orjuela-Quintana , Gabriela A. Valencia-Zuñiga , César A. Valenzuela-Toledo

The cosmic, general analitic solutions of the Brans--Dicke Theory for the flat space of homogeneous and isotropic models containing perfect, barotropic, fluids are seen to belong to a wider class of solutions --which includes cosmological…

General Relativity and Quantum Cosmology · Physics 2016-08-31 P. Chauvet , J. L. Cervantes-Cota

We study the scalar modes of linear perturbations in loop quantum cosmology. This is done on a lattice where each cell is taken to be homogeneous and isotropic and can be quantized via standard homogeneous loop quantum cosmology techniques.…

General Relativity and Quantum Cosmology · Physics 2015-06-05 Edward Wilson-Ewing

The Cosmological Principle, the combined assumptions of cosmological isotropy and homogeneity, underpins the standard model of Big Bang cosmology with which we interpret astronomical observations. A new test of isotropy over the redshift…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-02 E. O. Zavarygin , J. K. Webb
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