2025/03/26 by Zhang, Weibing, Zhao, Ruiyang, Mu, Xiaoyong +4
#Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2503.20574
In this work, we investigate a joint fitting approach based on theoretical models of power spectra associated with density-field reconstruction. Specifically, we consider the matter auto-power spectra before and after baryon acoustic oscillation (BAO) reconstruction, as well as the cross-power spectrum between the pre- and post-reconstructed density fields. We present redshift-space models for these three power spectra at the one-loop level within the framework of standard perturbation theory (SPT), and perform a joint analysis using three types of power spectra, and quantify their impact on parameter constraints. When restricting the analysis to wavenumbers k ≤ 0.2 h Mpc-1 and adopting a smoothing scale of Rs = 15 h-1 Mpc, we find that incorporating all three power spectra improves parameter constraints by approximately 11%--16% compared to using only the post-reconstruction power spectrum, with the Figure of Merit (FoM) increasing by 10.5%. These results highlight the advantages of leveraging multiple power spectra in BAO reconstruction, ultimately enabling more precise cosmological parameter estimation.