English

Model-independent determination of cosmic curvature based on Pad\'{e} approximation

Cosmology and Nongalactic Astrophysics 2020-01-08 v1

Abstract

Given observations of the standard candles and the cosmic chronometers, we apply Pad\'{e} parameterization to the comoving distance and the Hubble paramter to find how stringent the constraint is set to the curvature parameter by the data. A weak informative prior is introduced in the modeling process to keep the inference away from the singularities. Bayesian evidence for different order of Pad\'{e} parameterizations is evaluated during the inference to select the most suitable parameterization in light of the data. The data we used prefer a parameterization form of comoving distance as D01(z)=a0z1+b1zD_{01}(z)=\frac{a_0 z}{1+b_1 z} as well as a competitive form D02(z)=a0z1+b1z+b2z2D_{02}(z)=\frac{a_0 z}{1+b_1 z + b_2 z^2}. Similar constraints on the spatial curvature parameter are established by those models and given the Hubble constant as a byproduct: Ωk=0.250.13+0.14\Omega_k = 0.25^{+0.14}_{-0.13} (68\% confidence level [C.L.]), H0=67.7±2.0H_0 = 67.7 \pm 2.0 km/s/Mpc (68\% C.L.) for D01D_{01}, and Ωk=0.01±0.13\Omega_k = -0.01 \pm 0.13 (68\% C.L.), H0=68.8±2.0H_0 = 68.8 \pm 2.0 km/s/Mpc (68\% C.L.) for D02D_{02}. The evidence of different models demonstrates the qualitative analysis of the Pad\'{e} parameterizations for the comoving distance.

Keywords

Cite

@article{arxiv.1910.09794,
  title  = {Model-independent determination of cosmic curvature based on Pad\'{e} approximation},
  author = {Shi-Yu Li and Yun-Long Li and Tong-Jie Zhang and Tingting Zhang},
  journal= {arXiv preprint arXiv:1910.09794},
  year   = {2020}
}

Comments

8 pages, 2 figures, submitted to ApJ