Dependence of Cosmological Constraints on Gray Photometric Zero-point Uncertainties of Supernova Surveys

Journal Article (Journal Article)

Type Ia supernova (SN) measurements of the Hubble constant, H 0; cosmic mass density, ΩM ; and dark energy equation-of-state parameter, w, rely on heterogeneous SN surveys across three decades of observation. These distinct surveys may have undiagnosed, relative photometric zero-point errors. We determine the sensitivities of the SH0ES+Pantheon+ cosmological constraints to unknown gray systematics in the photometric zero-point calibration between the 19 surveys that comprise the Pantheon+ SN compendium. Varying the surveys’ gray zero-points simultaneously with cosmological parameters, we determine that the SH0ES+Pantheon+ measurement of H 0 is robust against gray intersurvey photometric miscalibration. Specifically, uncalibrated intersurvey systematics could represent a source of uncertainty no larger than 0.39 km s−1 Mpc−1 for H 0. This modest increase in H 0 uncertainty could not account for the 7 km s−1 Mpc−1 “Hubble tension” between the SH0ES measurement of H 0 and the Planck ΛCDM-based inference of H 0. However, the SH0ES+Pantheon+ best-fit values of ΩM and w are not robust against gray zero-point error, slipping by up to 0.16 and −0.63. Because measurements of ΩM and w depend on intrasurvey cross-band calibration, the hypothetical gray miscalibration underestimates the sensitivity of these measurements to zero-point miscalibration. Because the Pantheon+ compendium contains many surveys that share low-z Hubble flow (HF) and Cepheid-paired SNe, intersurvey photometric calibration errors do not significantly impede the joint use of SH0ES and Pantheon+ to measure H 0 to 1% accuracy. However, H 0 constraints that rely on one HF survey but numerous galactic distance calibration surveys are susceptible to intersurvey photometric miscalibration.

Full Text

Duke Authors

Cited Authors

  • Brownsberger, SR; Brout, D; Scolnic, D; Stubbs, CW; Riess, AG

Published Date

  • February 1, 2023

Published In

Volume / Issue

  • 944 / 2

Electronic International Standard Serial Number (EISSN)

  • 1538-4357

International Standard Serial Number (ISSN)

  • 0004-637X

Digital Object Identifier (DOI)

  • 10.3847/1538-4357/acad80

Citation Source

  • Scopus