The Pantheon+ Analysis: SuperCal-fragilistic Cross Calibration, Retrained SALT2 Light-curve Model, and Calibration Systematic Uncertainty

Abstract We present a recalibration of the photometric systems in Pantheon+ sample Type Ia supernovae (SNe Ia) including those SH0ES distance-ladder measurement H 0 . utilize large and uniform sky coverage public Pan-STARRS stellar photometry catalog to cross calibrate against tertiary standards released by individual SN surveys. The most significant updates over “SuperCal” calibration used for previous Pantheon analyses are: (1) expansion number (now 25) filters 105), (2) solving all filter offsets simultaneously produce uncertainty covariance matrix cosmological-model constraints, (3) accounting change fundamental flux Hubble Space Telescope CALSPEC from versions on order 1.5% ? ? 4000 Å. retrain SALT2 model find that our new coupled with light curves themselves causes net distance modulus ( d ? / dz ) 0.04 mag redshift range < z 1. introduce formalism determine systematic impact cosmological inference propagating fitted through retraining light-curve fitting total ? w = 0.013; roughly half size statistical uncertainty. Similarly, we contribution is less than 0.2 km s ?1 Mpc , suggesting cannot resolve current level “Hubble Tension.”