Over-Luminous Type Ia Supernovae and Standard Candle Cosmology

Type Ia supernovae (SNe Ia) serve as crucial cosmological distance indicators because of their empirical consistency in peak luminosity and characteristic light curve decline rates. These properties facilitate them to be standardized candles for the determination of the Hubble constant (H₀) within late-time universe cosmology. Nevertheless, a statistically significant difference persists between H₀ values derived from early and late-time measurements, a phenomenon known as the Hubble tension. Furthermore, recent observations have identified a subset of over-luminous SNe Ia, characterized by peak luminosities exceeding the nominal range and faster decline rates. These discoveries raise questions regarding the reliability of SNe Ia as standard candles for measuring cosmological distances. In this article, we present the Bayesian analysis of eight over-luminous SNe Ia and show that they yield a lower H₀ estimate, exhibiting closer concordance with H₀ estimates derived from early-universe data. This investigation potentially represents a step toward addressing the Hubble tension.