Non-parametric reconstruction of dark energy and cosmic expansion from the Pantheon compilation of type Ia supernovae *

Abstract

The equation of state (EoS) of dark energy plays an important role in the evolution of the universe and arouses great interests in recent years. With the progress on observational technique, precise constraint on the EoS of dark energy becomes possible. In this paper, we reconstruct the EoS of dark energy and cosmic expansion using Gaussian processes (GP) from the most up-to-date Pantheon compilation of type Ia supernovae (SNe Ia), which consists of 1048 finely calibrated SNe Ia. The reconstructed EoS of dark energy has large uncertainty due to its dependence on the second order derivative of the construction. Adding the direct measurements of Hubble parameters H(z) as an additional constraint on the first order derivative can partially reduce the uncertainty, but is still not precise enough to distinguish between evolving and constant dark energy. Besides, the results heavily rely on the prior of Hubble constant H 0 . The H 0 value inferred from SNe+H(z) without prior is H 0 = 70.5 ± 0.5 km s −1 Mpc −1 . Moreover, the matter density Ω M has an unnegligible effect on the reconstruction of dark energy. Therefore, more accurate determinations on H 0 and Ω M are needed to tightly constrain the EoS of dark energy.

The Logotropic Dark Fluid: Observational and Thermodynamic Constraints

“…In particular, we have obtained Ω m0 = 0.253 +0.031 −0.027 and H 0 = 70.35 +2.49 −2.50 km s −1 Mpc −1 , which is in agreement with the recent estimate obtained H 0 = 70.5 +0.5 −0.5 km s −1 Mpc −1 in Ref. [53]. As mentioned in section IV, our detailed study shows that the deduced Hubble constant H 0 is approximately the mean value of the global and local measurements of H 0 , and thus alleviating the tension between these measurements.…”

“…It has been observed that the value of Ω m0 obtained in this work is lower than the value obtained by the Planck analysis [55], which puts the limit on Ω m0 as Ω m0 = 0.315 ± 0.017 with 1σ errors [55]. Interestingly, it has been found that the best-fit value of the parameter H 0 obtained in the present analysis is almost same with the value H 0 = 70.5 +0.5 −0.5 km s −1 Mpc −1 , obtained by the Lin et al [53], using the Pantheon compilation of type Ia supernovae and the non-parametric method. On the other hand, it is well known that there is more than 3σ tension between the values of H 0 measured from the global CMB radiation (H 0 = 67.4 +0.5 −0.5 km s…”

Nonparametric reconstruction of interaction in the cosmic dark sector

“…[45][46][47][48][49][50][51][52]. Recently the non-parametric approach finds relevance in the reconstruction of kinematical quantities like the deceleration parameter q [53][54][55][56][57][58][59][60] and the jerk parameter j [61].…”

Sparse Formulae for the Distance Modulus in Cosmology

“…in Equation (14). Despite of this fact the FORTRAN code which derives the cosmological parameters produces a small difference in the results because the variables are evaluated in a different way.…”

“…The availability of SN compilations allows testing old and new cosmological models. We select some of them among others: cosmological relativity in five spatial dimensions [9], an improvement of the Einstein-De Sitter cosmology [10], the ( ) f R gravity with additional logarithmic corrections [11] [12], influence of the detection of gravitational waves on a definitive theory of gravity [13], the derivation of the value of the Hubble constant as ( ) the dark energy cosmology [14] and the deduction of the parameters for Starobinsky gravity [15]. This paper reviews, in Section 2, old and new distance moduli in twelve cosmologies.…”