Year: 2025
Type: article
Abstract: We present constraints on the baryonic matter density parameter, Ω b , within the framework of the ΛCDM model. Our analysis utilizes observational data on the effective optical depth from high-redshift quasars. To parameterize the photoionization rate Γ−12, we employ a Bézier polynomial. Additionally, we approximate the Hubble parameter at high redshifts as H ( z ) ≈ 100 h Ω m 1 / 2 ( 1 + z ) 3 / 2 km s−1 Mpc−1. Confidence regions are obtained with h = 0.701 ± 0.013 and Ω m = 0.315, optimized by the Planck mission. The best-fit values are Ω b = 0.04 3 − 0.006 + 0.005 and Ω b = 0.04 5 − 0.006 + 0.004 , corresponding to an old data set and a new data set, respectively. We test the non-parametric form of Γ−12, obtaining Ω b = 0.04 8 − 0.003 + 0.001 . These results are consistent with the findings of Planck at the 1σ confidence level. Our findings underscore the effectiveness of quasar data sets in constraining Ω b , eliminating the need for independent photoionization rate data. This approach provides detailed cosmic information about baryon density and the photoionization history of the intergalactic medium.
Authors: Wen-Fei Liu, Yuan-Bo Xie, Zhi-E Liu, Jin Qin, Kang Jiao, Dong-Yao Zhao, Tong-Jie 同杰 Zhang 张
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4407062419