The Cosmic Linear Anisotropy Solving System (CLASS). Part II: Approximation schemes
École Polytechnique Fédérale de Lausanne · Centre National de la Recherche Scientifique · +4 more institutions
Abstract
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 from 10 4 to 10 5 Boltzmann code executions. The newly released code CLASS (Cosmic Linear Anisotropy Solving System) incorporates improved approximation schemes leading to a simultaneous gain in speed and precision. We describe here the three approximations used by CLASS for basic ΛCDM models, namely: a baryon-photon tight-coupling approximation which can be set to first order, second order or to a compromise between the two; an ultra-relativistic fluid approximation which had…
Citation impact
- FWCI
- 19.05
- Percentile
- 100%
- References
- 34
Authors
3- DBDiego BlasCorresponding
École Polytechnique Fédérale de Lausanne
- JLJ Lesgourgues
Centre National de la Recherche Scientifique, Laboratoire d'Annecy de Physique Théorique, École Polytechnique Fédérale de Lausanne, European Organization for Nuclear Research, Université Savoie Mont Blanc
- TTThomas Tram
Aarhus University, European Organization for Nuclear Research
Topics & keywords
- Physics
- Cosmic microwave background
- Boltzmann constant
- Statistical physics
- COSMIC cancer database
- Boltzmann equation
- Anisotropy
- Class (philosophy)