A consistent, physical, and analytical model for cosmic microwave background observables of reionisation. I. Derivation, constraining power, and detectability of the auto spectra
Year: 2026
Type: article
Abstract: The epoch of reionisation imprints its history and morphology on the cosmic microwave background temperature and polarisation anisotropies through two effects: the kinetic Sunyaev Zel'dovich (kSZ) effect and Thomson scattering. To perform joint analyses of these observables and put tight constraints on the reionisation history and morphology, a common reionisation model is required. We present a quick, physically accurate analytical approach to consistently deriving the angular power spectra of the three main resulting imprints: the spatial fluctuations of the Thomson optical depth, patchy kSZ effect, and scattering and screening B-modes. The approach differs from existing analytical models, as it is calibrated on high-resolution hydrodynamical simulations and depends on the physical parameters of reionisation. Our predicted power spectra are consistent with the ones derived from cosmological simulations, whilst including more physical information, such as the typical size of ionised bubbles and the duration of reionisation. We provide an updated detectability assessment and show that both C_ and C_ Python package. could be measured by experiments similar to CMB Stage 4 and CMB-HD, respectively. We demonstrate the complementarity of the three observables in constraining reionisation history and morphology, and we also illustrate the potential of their joint analysis to get a global picture of reionisation. This analytical model will be a powerful tool for analyses of upcoming CMB data, either individually or in combination with independent datasets such as measurements of the high-redshift 21,cm signal. The code to derive these spectra is publicly available online as the preion
Source: Astronomy and Astrophysics
Author: Adélie Gorce
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Funder: Agence Nationale de la Recherche
OpenAlex ID: W7223086621