2013/10/31 by Shuang Wang, Yun-He Li, Xin Zhang · 3 citations
Physics and Astronomy · #astro-ph.CO #gr-qc
paper · pdf · doi:10.1103/physrevd.89.063524
published as Phys. Rev. D 89, 063524 (2014) · 11 pages, 9 figures, 2 tables; accepted for publication in Physical Review D. arXiv admin note: text overlap with arXiv:1306.6423; and with arXiv:1109.3172 by other authors
arxiv created 2014/03/03 · arxiv updated 2014/03/25
It has been found in previous studies that, for the Supernova Legacy Survey three-year (SNLS3) data, there is strong evidence for the redshift-evolution of color-luminosity parameter β. In this paper, using three simplest dark energy models (ΛCDM, wCDM, and CPL), we further explore the evolution of β and its effects on parameter estimation. In addition to the SNLS3 data, we also take into account the Planck distance priors data, as well as the latest galaxy clustering (GC) data extracted from SDSS DR7 and BOSS. We find that, for all the models, adding a parameter of β can reduce χ2min by ∼ 36, indicating that β1 = 0 is ruled out at 6σ confidence levels. In other words, β deviates from a constant at 6σ confidence levels. This conclusion is insensitive to the dark energy models considered, showing the importance of considering the evolution of β in the cosmology-fits. Furthermore, it is found that varying β can significantly change the fitting results of various cosmological parameters: using the SNLS3 data alone, varying β yields a larger Ωm for the ΛCDM model; using the SNLS3+CMB+GC data, varying β yields a larger Ωm and a smaller h for all the models. Moreover, we find that these results are much closer to those given by the CMB+GC data, compared to the cases of treating β as a constant. This indicates that considering the evolution of β is very helpful for reducing the tension between supernova and other cosmological observations.