Model-independent determination on H 0 using the latest cosmic chronometer data

Abstract

We perform the improved constraints on the Hubble constant H0 by using the model-independent method, Gaussian Processes. Utilizing the latest 36 H(z) measurements, we obtain H0 = 69.21±3.72 km s −1 Mpc −1 , which is consistent with the Planck 2015 and Riess et al. 2016 analysis at 1σ confidence level, and reduces the uncertainty from 6.5% (Busti et al. 2014) to 5.4%. Different from the results of Busti et al. 2014 by only using 19 H(z) measurements, our reconstruction results of H(z) and the derived values of H0 are independent of the choice of covariance functions. I. INTRODUCTIONAn urgent task in modern cosmology is to measure the Hubble constant H 0 accurately, since it brings substantially important information of the universe such as the size and age of the universe, the present cosmic expansion rate and the cosmic components. Due to the early determination by Hubble [1], the value of H 0 was believed to lie in the relatively large range [50, 100] km s −1 Mpc −1 for a long time [2]. With the use of different calibration techniques and improved control of systematics, the first accurate value, H 0 = 72 ± 8 km s −1 Mpc −1 [3], was given by the local measurements from the Hubble Space Telescope in 2001. After ten years, Riess et al. calibrated the Type Ia supernovae (SNe Ia) and obtained H 0 = 73.8 ± 2.4 km s −1 Mpc −1 [4] by using three indicators, i.e., the distance to NGC 4258 from a megamaser measurement, the trigonometric parallaxes measurements to the Milk Way (MW) Cepheids, Cepheid observations and a modified distance to the Large Magellanic Cloud (LMC). In 2012, there are three groups to measure the Hubble constant: Riess et al. got H 0 = 75.4±2.9 km s −1 Mpc −1 by utilizing the Cepheids in M31 [5]; Freedman et al. obtained H 0 = 74.3 ± 2.1 km s −1 Mpc −1 by using a mid-infrared calibration for the Cepheids [6]; Cháves et al. got H 0 = 74.3 ± 3.1(random) ± 2.9 (syst.) km s −1 Mpc −1 by adopting HII regions and HII galaxies as distance indicators [7]. Subsequently, in 2013, H 0 = 67.3 ± 1.2 km s −1 Mpc −1 derived by Planck [8] from the anisotropies of the cosmic microwave background (CMB) exhibits a strong tension with the local measurement from Riess et al. 2011 at 2.4σ level. For the purpose to alleviate or resolve this tension, several groups implemented the measurements using different methods: Bennett et al. [9] and Hinshaw et al. [10] gave a 3% determination, namely, H 0 = 70.0 ± 2.2 km s −1 Mpc −1 by utilizing the nine-year Wilkinson Microwave Anisotropy Probe (WMAP9) data; Spergel et al. [11] found H 0 = 68.0 ± 1.1 km s −1 Mpc −1 by removing the 217 × 217 GHz detector set spectrum used in the Planck analysis; Fiorentino et al. [12] obtained H 0 = 76.0 ± 1.9 km s −1 Mpc −1 by using 8 new classical Cepheids observed in galaxies hosting SNe Ia; Different from the calibration method exhibited by Riess et al. 2011, Tammann et al. [13] got a lower value H 0 = 63.7 ± 2.3 km s −1 Mpc −1 by calibrating the SN Ia with the tip of red-giant branch (TRGB); Efstathiou [14] obtained H 0 = 70.6 ± 3.3 km s −1 Mpc...

Constraints on H0 from WMAP and BAO Measurements*

“…These measurements, independent of SH0ES and Planck constraints, seem to favor a lower H 0 value that is more consistent with Planck result. See [19][20][21][22][23][24][25][26][27][28][29][30] for more literature on H 0 .…”

An accelerating cosmological model from a parametrization of Hubble parameter

“…We have used the same method of minimizing Chi square value with an updated 36 points of observational Hubble dataset (OHD) as used in Ref. [47]. The error bar plot of 36 points of OHD and the contour plot in n-H 0 plane at 1-σ, 2-σ, 3-σ level are shown in FIG.12 (a) & (b).…”

“…The only model parameter involved in n and is chosen n = 1.43. (a) The error bar plot of H(z) vs. redshift 'z' and (b) The contour plot in n − H0 plane with the observational Hubble dataset[47] demonstrates the error bar plot of 36 points of OHD fitted with the ΛCDM model and our obtained model together with the constrained values of n and H 0 as a contour plot in n-H 0 plane at 1-σ, 2-σ, 3-σ level. The constrained values of the model parameter n is found to be n = 1.435 and H 0 = 67.102 with minimum Chi square value χ 2 min = 19.075.…”

Limits on the Reconstruction of a Single Dark Energy Scalar Field Potential from SNe Ia Data

“…We are using 26 H(z) non-SNe data points (we were using 26 data points, but at the time there could be found maximum of 36 non-SNe data points (chronometers, BAO etc. ), see e.g., [52], but one need to carefully investigate the nature of these data, their quality and errors before usage) -out of 30 from [50] we dropped four from [53], since their precision is much less then the rest of the data from [50].…”