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Breaking through the high redshift bottleneck of Observational Hubble parameter

更新时间:2017-05-22 16:20:03点击次数:753次字号:T|T
Yuan, Shuo; Zhang, Tong-Jie

Abstract

We propose a robust scheme to measure the Hubble parameter H(z) at high redshifts by detecting the Sandage-Loeb signal (SL signal) which can be realized by the next generation extremely large telescope. It will largely extend the current observational Hubble parameter data (OHD) towards the redshift range of z in [2.0,5.0] where other dark energy probes is difficult to provide useful information of the cosmic expansion. To quantify the capability of such future measurement to constrain cosmological models, we simulate observational data for a CODEX (COsmic Dynamics and EXo-earth experiment)-like survey. We find that the SL signal scheme brings the redshift upper-limit of OHD from zmax = 2.3 to 0zmax simeq 5., provides more accurate constraints on different dark energy models, and greatly changes the degeneracy direction of the parameters. For the ΛCDM case, the accuracy of Ωm is improved by 58% and the degeneracy between Ωm and ΩΛ is rotated to the vertical direction of Ωm - ΩΛ plane; for the wCDM case, the accuracy of w is improved by 15%. The Fisher matrix forecast on different time-dependent w(z) cosmological model is also performed.
Journal of Cosmology and Astroparticle Physics(JCA (编辑:admin)