Abstract

Planck's Hubble constant and 120 Supernovae Type Ia show that the expansion of our local Universe is decelerating

Author(s): Göran Henriksson

The Bayesian regression curve for 120 Supernovae Type Ia, Khetan et al., 2021, corresponds within the margin of errors to the Hubble constant H₀=67.4 kms^-1 Mpc^-1 determined by the Planck Collaboration in 2020. If we from this curve read which distance modulus μ that corresponds to the redshift z=0.08 we get μ=37.76. From an equation by Stephen Weinberg, published in 1972, we can now calculate the cosmic deceleration q₀=+1.060 ± 0.039. This possibility was found during a successful test of the Hubble constant H₀=67.3 kms^-1 Mpc^-1, determined from the BL Lac object AP Lib, against the calibration by Khetan et al. This means that H₀, determined by the Planck Collaboration in 2020, and the well-calibrated sample of Supernovae Type Ia, by Khetan et al., proves that the expansion of our local Universe is decelerating at least within the nearest 1 billion light years. The q₀=+1.075 value, from AP Lib, gives an independent support to this result because it falls within the limits of error q₀=+1.060 ± 0.039 of Planck's final result.