Revisit of constraints on holographic dark energy:SNLS3 dataset with the effects of time-varying β and different light-curve fitters  

作　　者：WANG Shuang GENG JiaJia HU YiLiang ZHANG Xin 

机构地区：[1]Department of Physics, College of Sciences, Northeastern University [2]Center for High Energy Physics, Peking University

出　　处：《Science China(Physics,Mechanics & Astronomy)》2015年第1期150-160,共11页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.11405024 and 11175042);the Fundamental Research Fundsfor the Central Universities(Grant Nos.N130305007 and N120505003)

摘　　要：Previous studies have shown that for the Supernova Legacy Survey three-year （SNLS3） data there is strong evidence for the redshifl- evolution of color-luminosity parameter β of type Ia supernovae （SN Ia）. In this paper, we explore the effects of varying β on the cosmological constraints of holographic dark energy （HDE） model. In addition to the SNLS3 data, we also use Planck distance prior data of cosmic microwave background （CMB）, as well as galaxy clustering （GC） data extracted from Sloan Digital Sky Survey （SDSS） data release 7 and Baryon Oscillation Spectroscopic Survey （BOSS）. We find that, for the both cases of using SN data alone and using SN＋CMB＋GC data, involving an additional parameter of β can reduce χ^2 by - 36; this shows that β deviates from a constant at 6σ- confidence levels. Adopting SN＋CMB＋GC data, we find that compared to the constant β case, varying β yields a larger fractional matter density Ωm0 and a smaller reduced Hubble constant h; moreover, varying β significantly increases the value of HDE model parameter c, leading to c ≈ 0.8, consistent with the constraint results obtained before Planck. These results indicate that the evolution of β should be taken into account seriously in the cosmological fits. In addition, we find that relative to the differences between the constant β and varying β（z） cases, the effects of different light-curve fitters on parameter estimation are very small.Previous studies have shown that for the Supernova Legacy Survey three-year(SNLS3)data there is strong evidence for the redshiftevolution of color-luminosity parameterβof type Ia supernovae(SN Ia).In this paper,we explore the effects of varyingβon the cosmological constraints of holographic dark energy(HDE)model.In addition to the SNLS3 data,we also use Planck distance prior data of cosmic microwave background(CMB),as well as galaxy clustering(GC)data extracted from Sloan Digital Sky Survey(SDSS)data release 7 and Baryon Oscillation Spectroscopic Survey(BOSS).We find that,for the both cases of using SN data alone and using SN+CMB+GC data,involving an additional parameter ofβcan reduceχ2by～36;this shows thatβdeviates from a constant at 6σconfidence levels.Adopting SN+CMB+GC data,we find that compared to the constantβcase,varyingβyields a larger fractional matter density-m0and a smaller reduced Hubble constant h;moreover,varyingβsignificantly increases the value of HDE model parameter c,leading to c≈0.8,consistent with the constraint results obtained before Planck.These results indicate that the evolution ofβshould be taken into account seriously in the cosmological fits.In addition,we find that relative to the differences between the constantβand varyingβ(z)cases,the effects of different light-curve fitters on parameter estimation are very small.

关 键 词：cosmological constraints holographic dark energy type Ia supernova time-varying β 

分 类 号：P159[天文地球—天文学]