2023/08/09 by Bohdan Bidenko, L. V. E. Koopmans, Bidenko, Bohdan +3
Mathematics · Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Gamma-ray bursts and supernovae #Statistical and numerical algorithms
paper · pdf · doi:10.48550/arxiv.2308.05157
openalex publication_date 2023/08/09 · openalex created_date 2023/08/12 · openalex updated_date 2026/07/28
Inspired by the discussion in the community on possible hidden systematic errors in late universe cosmological probes and non-trivial physical models developed to reduce the Hubble tension, we investigate the Pantheon and Pantheon+ SNe samples for possible deviations from the original ΛCDM analysis. To simultaneously account for possible systematics or deviations from ΛCDM, we adopt Gaussian processes to model additional covariance while making no further assumptions on their origin. We explore both stationary and non-stationarity corrections to the covariance. While small changes in the inferred cosmological parameters H0 and Ωm can occur, we find no statistically significant evidence for missing covariance. We find an upper limit for the Gaussian processes amplitude σ< 0.031 mag with 95% confidence, which corresponds to 20% of the average statistical error in the Pantheon+ sample. The strongest effect we find on the inferred cosmological parameter posterior can reduce the statistical significance of the Hubble tension between Pantheon+ and Planck estimates from 5.3σ to 4.5σ. Therefore, we conclude that the SN cosmological parameter inference is robust against the analysis modifications studied in this work.