The effects of parametrization of the dark energy equation of state  

作　　者：Ke Shi Yong-Feng Huang1,2 Tan Lu 

机构地区：[1]Department of Astronomy, Nanjing University, Nanjing 210093, China [2]Key Laboratory of Modern Astronomy and Astrophysics, Nanjing University, Nanjing 210093, China [3]Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China [4]Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing University - Purple Mountain Observatory, Nanjing 210093, China

出　　处：《Research in Astronomy and Astrophysics》2011年第12期1403-1412,共10页天文和天体物理学研究（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 10625313,10973039 and 11033002);the National Basic Research Program of China (973 program; GrantNo. 2009CB824800)

摘　　要：We investigate in detail the influence of parametrizations of the dark energy equation of state on reconstructing dark energy geometrical parameters, such as the deceleration parameter q（z） and Om diagnostic. We use a type Ia supernova sample, baryon acoustic oscillation data, cosmic microwave background information along with twelve observational Hubble data points to constrain cosmological parameters. With the joint analysis of these current datasets, we find that the parametrizations of w（z） have little influence on the reconstruction result of q（z） and Ore. The same is true for the transition （cosmic deceleration to acceleration） redshift zt, for which we find that for different parametrizations of w（z）, the best fitted values of zt are very close to each other （about 0.65）. All of our results are in good agreement with the ACDM model. Furthermore, using the combination of datasets, we do not find any signal of decreasing cosmic acceleration as suggested in some recent papers. The results suggest that the influence of the prior w（z） is not as severe as one may anticipate, and thus we can, to some extent, safely use a reasonable parametrization of w（z） to reconstruct some other dark energy parameters （e.g. q（z）, Ore） with a combination of datasets.We investigate in detail the influence of parametrizations of the dark energy equation of state on reconstructing dark energy geometrical parameters, such as the deceleration parameter q（z） and Om diagnostic. We use a type Ia supernova sample, baryon acoustic oscillation data, cosmic microwave background information along with twelve observational Hubble data points to constrain cosmological parameters. With the joint analysis of these current datasets, we find that the parametrizations of w（z） have little influence on the reconstruction result of q（z） and Ore. The same is true for the transition （cosmic deceleration to acceleration） redshift zt, for which we find that for different parametrizations of w（z）, the best fitted values of zt are very close to each other （about 0.65）. All of our results are in good agreement with the ACDM model. Furthermore, using the combination of datasets, we do not find any signal of decreasing cosmic acceleration as suggested in some recent papers. The results suggest that the influence of the prior w（z） is not as severe as one may anticipate, and thus we can, to some extent, safely use a reasonable parametrization of w（z） to reconstruct some other dark energy parameters （e.g. q（z）, Ore） with a combination of datasets.

关 键 词：cosmology： observations -- cosmology： cosmological parameters 

分 类 号：P145.9[天文地球—天体物理] TQ013.1[天文地球—天文学]