Measurements of the Hubble Constant: Tensions in Perspective
By W. Freedman. Astrophysical Journal, 2021
456 citations recorded by the source corpus.
Measurement of the distances to nearby galaxies has improved rapidly in recent decades. The ever-present challenge is to reduce systematic effects, especially as greater distances are probed and the uncertainties become larger. In this paper, we combine several recent calibrations of the tip of the red giant branch (TRGB) method. These calibrations are internally self-consistent at the 1% level. New Gaia Early Data Release 3 data provide an additional consistency check at a (lower) 5% level of accuracy, a result of the well-documented Gaia angular covariance bias. The updated TRGB calibration applied to a sample of Type Ia supernovae from the Carnegie Supernova Project results in a value of the Hubble constant of H 0 = 69.8 ± 0.6 (stat) ± 1.6 (sys) km s−1 Mpc−1. No statistically significant difference is found between the value of H 0 based on the TRGB and that determined from the cosmic microwave background. The TRGB results are also consistent to within 2σ with the SHoES and Spitzer plus Hubble Space Telescope (HST) Key Project Cepheid calibrations. The TRGB results alone do not demand additional new physics beyond the standard (ΛCDM) cosmological model. They have the advantage of simplicity of the underlying physics (the core He flash) and small systematic uncertainties (from extinction, metallicity, and crowding). Finally, the strengths and weaknesses of both the TRGB and Cepheids are reviewed, and prospects for addressing the current discrepancy with future Gaia, HST, and James Webb Space Telescope observations are discussed. Resolving this discrepancy is essential for ascertaining if the claimed tension in H 0 between the locally measured and CMB-inferred values is physically motivated.
Subfields: Astronomy and Astrophysics, Instrumentation
View Paper: https://www.semanticscholar.org/paper/47c79f2535c68904daffc78f01aed0e7c130fd7d
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Citations in the corpus
- Rock ‘n’ roll solutions to the Hubble tension (2019, background): “The discrepancy of the present day Hubble parameter H 0 derived from local measurements [ 1– 22 ] and from cosmic microwave background Through the positions and spacing of the acoustic peaks present in CMB power spectra, the CMB is sensitive to H 0 via the well-measured angle θ s = r s /D M ( z ∗…”
- A buyer’s guide to the Hubble constant (2021, unknown): “More recently, an updated value of H0 1⁄4 69:8 0:6 (stat) 1:6 (sys) kms 1 Mpc 1 was published by Freedman (2021). New and updated values for MI based on the anchors of the LMC, SMC, NGC 4258 and galactic globular clusters are derived.”
- A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km s−1 Mpc−1 Uncertainty from the Hubble Space Telescope and the SH0ES Team (2021, methodology): “The 9 SNe in 7 EDD TRGB hosts are brighter than the 33 SNe Ia in 30 hosts without EDD and CCHP TRGB by 0.08± 0.05 mag as measured by Cepheids, which is consistent at 1.6σ with the sampling noise of the two sets (0.04 mag and 0.02 mag random error, respectively).”
- The Ups and Downs of Early Dark Energy solutions to the Hubble tension: A review of models, hints and constraints circa 2023 (2023, methodology): “6 (sys)) km/s/Mpc [15, 26], in between the Planck CMB prediction and the SH0ES calibration measurement, and a re-analysis of the CCHP data by Anand et al.”
- On the Evolution of the Hubble Constant with the SNe Ia Pantheon Sample and Baryon Acoustic Oscillations: A Feasibility Study for GRB-Cosmology in 2030 (2022, methodology): “[117] test seven cosmological models through the constraints of SNe Ia, BAO, CMB, Planck lensing, and Cosmic Chronometers with the outcome that in the ΛCDM scenario a flat universe is favored.”