Publication Date:
2016-06-17
Description:
In this work, by applying the red-shift tomography method to the Joint Light-curve Analysis (JLA) supernova sample, we explore the possible red-shift dependence of the stretch luminosity α and the colour luminosity β. The basic idea is to divide the JLA sample into different red-shift bins, assuming that α and β are piecewise constants. Then, by constraining the CDM model, we check the consistency of the cosmology-fitting results given by the supernova sample of each red-shift bin. We also adopt the same technique to explore the possible evolution of β in various subsamples of JLA. Using the full JLA data, we find that α is always consistent with a constant value. In contrast, at high red shift, β has a significant trend of decreasing, at ~3.5 confidence level (CL). Moreover, we find that the low- z subsample favours a constant β; in contrast, the Sloan Digital Sky Survey and Supernova Legacy Survey subsamples favour a decreasing β at 2 and 3.3 CL, respectively. Besides, by using a binned parametrization of β, we study the impact of the evolution of β on parameter estimation. We find that compared with a constant β, a varying β yields a larger best-fitting value of fractional matter density m 0 , which slightly deviates from the best-fitting result given by other cosmological observations. However, for both the varying β and the constant β cases, the 1 regions of m 0 are still consistent with the result given by other observations.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
