Novel Cosmological Joint Constraints in Multidimensional Observables Space with Redshift-free Inferences

作     者：Hong, Wei Jiao, Kang Wang, Yu-Chen Zhang, Tingting Zhang, Tong-Jie 

作者机构：Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Beijing102206 China Department of Astronomy Beijing Normal University Beijing100875 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China Department of Astronomy School of Physics Peking University Beijing100871 China College of Command and Control Engineering Army Engineering University Nanjing210017 China 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2023年

核心收录：

主　　题：Cosmology 

摘      要：Cosmology constraints serve as a crucial criterion in discriminating cosmological models. The traditional combined method to constrain the cosmological parameters designates the corresponding theoretical value and observational data as functions of redshift, however, sometimes the redshift cannot be measured directly, or the measurement error is large, or the definition of redshift is controversial. In this paper, we propose a novel joint method to constrain parameters that eliminates the redshift z and makes full use of the multiple observables {F1,obs, F2,obs, · · ·, FM,obs} spanning in M-dimensional joint observables space. Considering the generality of the mathematical form of the cosmological models and the guidance from low to high dimensions, we firstly validate our method in a three-dimensional joint observables space spanned by H(z), fσ8(z) and DA(z), where the three coordinates can be considered redshift-free measurements of the same celestial body (or shared-redshift data reconstructed model independently). Our results are consistent with the traditional combined method but with lower errors, yielding H0 = 68.7 ±0.1 km s−1 Mpc−1, Ωm0 = 0.289 ±0.003, σ8 = 0.82 ±0.01 and showing alleviated parametric degeneracies to some extent. In principle, our joint constraint method allows an extended form keeping the redshift information as an independent coordinate and can also be readilydegraded to the form of a traditional combined method to constrain parameters. Copyright © 2023, The Authors. All rights reserved.