Cosmological analyses with type Ia supernovae (SNe Ia) often assume a single empirical relation between colour and luminosity (beta) and do not account for varying host-galaxy dust properties. However, from studies of dust in large samples of galaxies, it is known that dust attenuation can vary significantly. Here, we take advantage of state-of-the-art modelling of galaxy properties to characterize dust parameters (dust attenuation A(V), and a parameter describing the dust law slope R-V) for 1100 Dark Energy Survey (DES) SN host galaxies. Utilizing optical and infrared data of the hosts alone, we find three key aspects of host dust that impact SN cosmology: (1) there exists a large range (similar to 1-6) of host R-V; (2) high-stellar mass hosts have R-V on average similar to 0.7 lower than that of low-mass hosts; (3) for a subsample of 81 spectroscopically classified SNe there is a significant (>3 sigma) correlation between the Hubble diagram residuals of red SNe Ia and the host R-V that when corrected for reduces scatter by similar to 13 per cent and the significance of the 'mass step' to similar to 1 sigma . These represent independent confirmations of recent predictions based on dust that attempted to explain the puzzling 'mass step' and intrinsic scatter (sigma(int)) in SN Ia analyses.

The Dark Energy Survey Supernova Program results: type Ia supernova brightness correlates with host galaxy dust

Costanzi, M.;
2023-01-01

Abstract

Cosmological analyses with type Ia supernovae (SNe Ia) often assume a single empirical relation between colour and luminosity (beta) and do not account for varying host-galaxy dust properties. However, from studies of dust in large samples of galaxies, it is known that dust attenuation can vary significantly. Here, we take advantage of state-of-the-art modelling of galaxy properties to characterize dust parameters (dust attenuation A(V), and a parameter describing the dust law slope R-V) for 1100 Dark Energy Survey (DES) SN host galaxies. Utilizing optical and infrared data of the hosts alone, we find three key aspects of host dust that impact SN cosmology: (1) there exists a large range (similar to 1-6) of host R-V; (2) high-stellar mass hosts have R-V on average similar to 0.7 lower than that of low-mass hosts; (3) for a subsample of 81 spectroscopically classified SNe there is a significant (>3 sigma) correlation between the Hubble diagram residuals of red SNe Ia and the host R-V that when corrected for reduces scatter by similar to 13 per cent and the significance of the 'mass step' to similar to 1 sigma . These represent independent confirmations of recent predictions based on dust that attempted to explain the puzzling 'mass step' and intrinsic scatter (sigma(int)) in SN Ia analyses.
2023
Pubblicato
https://academic.oup.com/mnras/article/518/2/1985/6775122
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/3037681
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