2012/07/31 by Cong Zhang, Han Zhang, Shuo Yuan +3 · 4 citations
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1088/1674--4527/14/10/002
published as Research in Astronomy and Astrophysics 14 (2014) 1221-1233 · 14 pages, 7 figures, 4 tables, accepted by RAA for publication
arxiv created 2014/05/22 · arxiv updated 2014/10/24
By adopting the differential age method, we utilize selected 17832 luminous red galaxies (LRGs) from Sloan Digital Sky Survey Data Release Seven (SDSS DR7) covering redshift 0<z<0.4 to measure Hubble parameters. Using a full spectrum fitting package UlySS, these spectra are reduced with single stellar population (SSP) models and optimal age information of our selected sample are derived. With the decreasing age-redshift relation, four new observational H(z) data (OHD) points are obtained, which are H(z)=69.0±19.6 km s-1 Mpc-1 at z=0.07, H(z)=68.6±26.2 km s-1 Mpc-1 at z=0.12, H(z)=72.9±29.6 km s-1 Mpc-1 at z=0.2 and H(z)=88.8±36.6 km s-1 Mpc-1 at z=0.28, respectively. Combined with other 21 available OHD data points, a performance of constraint on both flat and non-flat ΛCDM model is presented.