| 摘要: |
In this work, we compare the impacts given by chi(2) statistics and Bayesian statistics. Bayesian statistics is a new statistical method proposed by [C. Ma, P. S. Corasaniti, and B. A. Bassett, arXiv:1603.08519[astro-ph.CO](2016)] recently, which gives a fully account for the standard-candle parameter dependence of the data covariance matrix. For this two statistical methods, we explore the possible redshift-dependence of stretch-luminosity parameter alpha and color-luminosity parameter beta by using redshift tomography. By constraining the ACDM model, we check the consistency of cosmology-fit results given by the SN sample of each redshift bin. We also adopt the linear parametrization to explore the possible evolution of alpha and beta and the deceleration parameter q(z) for CPL, JBP, BA and Wang models. We find that: (i) Using the full JLA data, at high redshift alpha has a trend of decreasing at more than 1.5 sigma confidence level (CL), and beta has a significant trend of decreasing at more than 19 sigma CL. (ii) Compared with chi(2) statistics (constant alpha, beta) and Bayesian statistics (constant alpha, beta), Bayesian statistics (linear alpha and beta) yields a larger best-fit value of fractional matter density Omega(m)(0) from JLA+CMB+GC data, which is much closer to slightly deviates from the best-fit result given by other cosmological observations. (iii) The figure of merit (FoM) given by JLA+CMB+GC data from Bayesian statistics is also larger than the FoM from chi(2) statistics, which indicates that former statistics has a better accuracy. (iv) q(z) given by both statistical methods favor an eternal cosmic acceleration at 1 sigma CL. |
