Thomas Tram

TL;DR: Three approximations used by CLASS for basic �CDM models are described, 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 not been implemented in public distributions before; and finally a radiation streaming approximation taking reionisation into account.

TL;DR: In this article, the newly released code CLASS (Cosmic Linear Anisotropy Solving System) incorporates improved approximation schemes leading to a simultaneous gain in speed and precision, namely a baryon-photon tight-coupling approximation which can be set to first order, second order or to a compromise between the two.

TL;DR: In this article, the authors 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.

TL;DR: It is shown that new interactions in the sterile neutrino sector can prevent their production in the early Universe and reconcile short baseline oscillation experiments with cosmology.

TL;DR: In this article, a coupled quintessence model with pure momentum exchange was proposed and the effects of such an interaction on the cosmic microwave background (CMB) and matter power spectrum were investigated.