基于双中子星引力波标准汽笛法测量的哈勃参量对于宇宙学参数的限制能力的预言

The constraint ability of Hubble parameter by gravitational wave standard sirens on cosmological parameters

展示了一种新的测量哈勃参数(H(z))的方法的应用,并用定义品质因子的方式对其所得H(z)进行了评估.这种测量H(z)的方法基于对双中子星系统的引力波汽笛法的分析,其中利用了光度距离(dL)的各向异性.引力波的成功探测预示着引力波标准汽笛法潜在的可能性.在此之前对其相应效果进行预言和研究是十分必要的.把这种方法应用在几个比较主流的引力波探测项目上,并进行Fisher Matrix的计算,包括advanced LIGO(aLIGO)、Einstein telescope(ET)、DECIGO等.结果显示,aLIGO和ET测得的H(z)精度都比较差,而DECIGO测得的H(z)显示出良好的精度.利用DECOIGO得到的H(z)的相对误差信息,对H(z)进行模拟,然后用贝叶斯定理对宇宙学参量进行预言,最后利用画contour图和计算品质因子(FoM)方法评估出其限制宇宙学参量的能力.对于DECIGO 3a观测的引力波标准汽笛法,其相应H(z)数据的品质因子为170.82.如果进行10a期的观测,其相应H (z)数据的品质因子更是高达569.42.显示出引力波标准汽笛法的极大前景和潜力.

In this paper,we present a new method measuring Hubble parameter(H(z)),making use of the anisotropy of luminosity distance(dL),based on analysis of gravitational wave(GW)standard sirens of neutron star(NS)binary system.The method has never been put into practice due to inability to detect GW and corresponding electromagnetic counterpart.Last year the LIGO team detected GW of a binary neutron star system,and corresponding electromagnetic counterpart.This success announced potential possibility of GW standard sirens.Before actual detection,it is meaningful to do some investigation.We apply this new method to several GW detecting projects,including Advanced LIGO(aLIGO),Einstein Telescope(ET),DECIGO,and evaluate constraint ability on cosmological parameters of their H(z).We mainly use Fisher Matrix and Bayes theorem to do the calculation and analysis.We plot‘contour figure’of mock data and define‘Figure of Merit’(FoM)to evaluate constraint ability.It turns out that H(z)by aLIGO and ET is of poor accuracy,while H(z)by DECIGO shows good accuracy.We simulate H(z)data by python code at every 0.1 redshift span using error information of H(z)by DECIGO,and put mock data into forecasting of cosmological parameters.Compared with 38 actual observed H(z)data(OHD),mock data show a higher value of Figure of Merit(FoM,reciprocal of area enclosed by 2σconfidence region).For a 3-year-observation by standard sirens of DECIGO,FoM value is as high as 170.82.If a 10-year-observation is launched,FoM could reach 569.42.For comparison,FoM of 38 actual observed H(z)data(OHD)is 9.3.We also investigate undulant universe.These improvements indicate that the new method has great potential in further cosmological constraints.