Cosmological parameter fittings with the BICEP2 data

• Published in: Science China. Physics, mechanics & astronomy Vol. 57; no. 8; pp. 1449 - 1454
• Main Authors: Wu, FengQuan, Li, YiChao, Lu, YouJun, Chen, XueLei
• Format: Journal Article
• Language: English
• Published: Heidelberg Science China Press 01.08.2014; Springer Nature B.V
• Subjects: Anisotropy; Astronomy; Camber; Classical and Continuum Physics; Cosmic microwave background; DM模型; Fittings; Markov chains; Mathematical models; Microwave Anisotropy Probe; Monte Carlo methods; Observations and Techniques; Parameters; Physics; Physics and Astronomy; Power spectra; Tensors; Texts; Tilt; WMAP; 威尔金森微波各向异性探测器; 宇宙学参数; 宇宙微波背景辐射; 数据约束; 配件; 马尔可夫; mode; inflation; BICEP2
• ISSN: 1674-7348; 1869-1927
• DOI: 10.1007/s11433-014-5516-z

Combining the latest Planck, Wilkinson Microwave Anisotropy Probe （WMAP）, and baryon acoustic oscillation （BAO） data, we exploit the recent cosmic microwave background （CMB） B-mode power spectra data released by the BICEP2 collaboration to constrain the cosmological parameters of the ACDM model, especially the primordial power spectra parameters of the scalar and the tensor modes, ns, as, r, nt. We obtain constraints on the parameters for a lensed ACDM model using the Markov Chain -- ＋0,0307 ＋0,0061 ＋0,0105 Monte Carlo （MCMC） technique, the marginalized 68% bounds are r -0.1043 -0.0914, ns -0.9617-0.0061, as =-0.0175-0.0097, nt = 0.5198＋-0.4579. We find that a blue tilt for nt is favored slightly, but it is still well consistent with flat or even red tilt. Our r value is slightly smaller than the one obtained by the BICEP group, in that we permit nt as a free parameter without imposing the single-field slow roll inflation consistency relation. When we impose this relation, then r= 0.2130-0.06096 ＋0.0446. For most other parameters, the best fit values and measurement errors are not altered significantly by the introduction of the BICEP2 data.