### Abstract

We present a model-independent measurement of spatial curvature Ω_{k} in the Friedmann-Lemaitre-Robertson-Walker universe, based on observations of the Hubble parameter H(z) using cosmic chronometers, and a Gaussian process (GP) reconstruction of the H ii galaxy Hubble diagram. We show that the imposition of spatial flatness (i.e., Ω_{k} = 0) easily distinguishes between the Hubble constant measured with Planck and that based on the local distance ladder. We find an optimized curvature parameter ω_{k} = -0.120_{-0.147} ^{+0.168} when using the former (i.e., H_{0} = 67.66 ± 0.42 km s^{-1} Mpc^{-1}), and ω_{k} = -0.298_{-0.088} ^{+0.122} for the latter (H_{0} = 73.24 ± 1.74 Km s^{-1} Mpc^{-1}). The quoted uncertainties are extracted by Monte Carlo sampling, taking into consideration the covariances between the function and its derivative reconstructed by GP. These data therefore reveal that the condition of spatial flatness favors the Planck measurement, while ruling out the locally inferred Hubble constant as a true measure of the large-scale cosmic expansion rate at a confidence level of ∼3σ.

Original language | English (US) |
---|---|

Article number | 137 |

Journal | Astrophysical Journal |

Volume | 881 |

Issue number | 2 |

DOIs | |

State | Published - Aug 20 2019 |

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### Keywords

- cosmological parameters
- distance scale

### ASJC Scopus subject areas

- Astronomy and Astrophysics
- Space and Planetary Science

### Cite this

*Astrophysical Journal*,

*881*(2), [137]. https://doi.org/10.3847/1538-4357/ab2ed0

**Using Spatial Curvature with H.** / Ruan, Cheng Zong; Melia, Fulvio; Chen, Yu; Zhang, Tong Jie.

Research output: Contribution to journal › Article

*Astrophysical Journal*, vol. 881, no. 2, 137. https://doi.org/10.3847/1538-4357/ab2ed0

}

TY - JOUR

T1 - Using Spatial Curvature with H

AU - Ruan, Cheng Zong

AU - Melia, Fulvio

AU - Chen, Yu

AU - Zhang, Tong Jie

PY - 2019/8/20

Y1 - 2019/8/20

N2 - We present a model-independent measurement of spatial curvature Ωk in the Friedmann-Lemaitre-Robertson-Walker universe, based on observations of the Hubble parameter H(z) using cosmic chronometers, and a Gaussian process (GP) reconstruction of the H ii galaxy Hubble diagram. We show that the imposition of spatial flatness (i.e., Ωk = 0) easily distinguishes between the Hubble constant measured with Planck and that based on the local distance ladder. We find an optimized curvature parameter ωk = -0.120-0.147 +0.168 when using the former (i.e., H0 = 67.66 ± 0.42 km s-1 Mpc-1), and ωk = -0.298-0.088 +0.122 for the latter (H0 = 73.24 ± 1.74 Km s-1 Mpc-1). The quoted uncertainties are extracted by Monte Carlo sampling, taking into consideration the covariances between the function and its derivative reconstructed by GP. These data therefore reveal that the condition of spatial flatness favors the Planck measurement, while ruling out the locally inferred Hubble constant as a true measure of the large-scale cosmic expansion rate at a confidence level of ∼3σ.

AB - We present a model-independent measurement of spatial curvature Ωk in the Friedmann-Lemaitre-Robertson-Walker universe, based on observations of the Hubble parameter H(z) using cosmic chronometers, and a Gaussian process (GP) reconstruction of the H ii galaxy Hubble diagram. We show that the imposition of spatial flatness (i.e., Ωk = 0) easily distinguishes between the Hubble constant measured with Planck and that based on the local distance ladder. We find an optimized curvature parameter ωk = -0.120-0.147 +0.168 when using the former (i.e., H0 = 67.66 ± 0.42 km s-1 Mpc-1), and ωk = -0.298-0.088 +0.122 for the latter (H0 = 73.24 ± 1.74 Km s-1 Mpc-1). The quoted uncertainties are extracted by Monte Carlo sampling, taking into consideration the covariances between the function and its derivative reconstructed by GP. These data therefore reveal that the condition of spatial flatness favors the Planck measurement, while ruling out the locally inferred Hubble constant as a true measure of the large-scale cosmic expansion rate at a confidence level of ∼3σ.

KW - cosmological parameters

KW - distance scale

UR - http://www.scopus.com/inward/record.url?scp=85072343454&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85072343454&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/ab2ed0

DO - 10.3847/1538-4357/ab2ed0

M3 - Article

AN - SCOPUS:85072343454

VL - 881

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 137

ER -