Cosmological Model Insensitivity of Local H0 from the Cepheid Distance Ladder

The observed tension (∼9% difference) between the local distance ladder measurement of the Hubble constant, H0, and its value inferred from the cosmic microwave background could hint at new, exotic, cosmological physics. We test the impact of the assumption about the expansion history of the univers...

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Bibliographic Details
Published in:The Astrophysical journal 2020-05, Vol.894 (1)
Main Authors: Dhawan, S., Brout, D., Scolnic, D., Goobar, A., Riess, A. G., Miranda, V.
Format: Article
Language:English
Subjects:
Astronomical models
Astrophysics
Big Bang theory
Calibration
Cepheid variables
Computer simulation
Constraint modelling
Cosmic microwave background
Cosmological parameters
Cosmology
Covariance
Dark energy
Deceleration
Energy
Hubble constant
Red shift
Supernova
Systematics
Type Ia supernovae
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Summary:The observed tension (∼9% difference) between the local distance ladder measurement of the Hubble constant, H0, and its value inferred from the cosmic microwave background could hint at new, exotic, cosmological physics. We test the impact of the assumption about the expansion history of the universe ( ) on the local distance ladder estimate of H0. In the fiducial analysis, the Hubble flow Type Ia supernova (SN Ia) sample is truncated to z < 0.15, and the deceleration parameter (q0) is fixed to −0.55. We create realistic simulations of the calibrator and Pantheon samples, and account for a full systematics covariance between these two sets. We fit several physically motivated dark-energy models, and derive combined constraints from calibrator and Pantheon SNe Ia and simultaneously infer H0 and dark-energy properties. We find that the assumption on the dark-energy model does not significantly change the local distance ladder value of H0, with a maximum difference (ΔH0) between the inferred value for different models of 0.47 km , i.e., a 0.6% shift in H0, significantly smaller than the observed tension. Additional freedom in the dark-energy models does not increase the error in the inferred value of H0. Including systematics covariance between the calibrators, low-redshift SNe, and high-redshift SNe can induce small shifts in the inferred value for H0. The SN Ia systematics in this study contribute 0.8% to the total uncertainty of H0.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/ab7fb0