Ultralarge-scale approximations and galaxy clustering: Debiasing constraints on cosmological parameters - Faculté des Sciences de Sorbonne Université Accéder directement au contenu
Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2022

Ultralarge-scale approximations and galaxy clustering: Debiasing constraints on cosmological parameters

Résumé

Upcoming galaxy surveys will allow us to probe the growth of the cosmic large-scale structure with improved sensitivity compared to current missions, and will also map larger areas of the sky. This means that in addition to the increased precision in observations, future surveys will also access the ultralarge-scale regime, where commonly neglected effects such as lensing, redshift-space distortions, and relativistic corrections become important for calculating correlation functions of galaxy positions. At the same time, several approximations usually made in these calculations such as the Limber approximation break down at those scales. The need to abandon these approximations and simplifying assumptions at large scales creates severe issues for parameter estimation methods. On the one hand, exact calculations of theoretical angular power spectra become computationally expensive, and the need to perform them thousands of times to reconstruct posterior probability distributions for cosmological parameters makes the approach unfeasible. On the other hand, neglecting relativistic effects and relying on approximations may significantly bias the estimates of cosmological parameters. In this work, we quantify this bias and investigate how an incomplete modelling of various effects on ultralarge scales could lead to false detections of new physics beyond the standard ΛCDM model. Furthermore, we propose a simple debiasing method that allows us to recover true cosmologies without running the full parameter estimation pipeline with exact theoretical calculations. This method can therefore provide a fast way of obtaining accurate values of cosmological parameters and estimates of exact posterior probability distributions from ultralarge-scale observations.
Fichier principal
Vignette du fichier
stab3578.pdf (1.31 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

hal-03312441 , version 1 (23-03-2023)

Identifiants

Citer

Matteo Martinelli, Roohi Dalal, Fereshteh Majidi, Yashar Akrami, Stefano Camera, et al.. Ultralarge-scale approximations and galaxy clustering: Debiasing constraints on cosmological parameters. Monthly Notices of the Royal Astronomical Society, 2022, 510 (2), pp.1964-1977. ⟨10.1093/mnras/stab3578⟩. ⟨hal-03312441⟩
68 Consultations
20 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More