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arXiv · 2503.13904

Over-Luminous Type Ia Supernovae and Standard Candle Cosmology

Abhinandan Ravi·T. R. Govindarajan·Surajit Kalita
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Abstract

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 ($H_0$) within late-time universe cosmology. Nevertheless, a statistically significant difference persists between $H_0$ 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 15 over-luminous SNe\,Ia and show that they yield a lower $H_0$ estimate due to the increase in their absolute magnitude. This investigation potentially represents a step toward addressing the Hubble tension.

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Abhinandan Ravi, T. R. Govindarajan, Surajit Kalita. 2025-03-18. Over-Luminous Type Ia Supernovae and Standard Candle Cosmology. https://arxiv.org/abs/2503.13904

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