Concerning colour: The effect of environment on type Ia supernova colour in the dark energy survey. Issue 2 (19th December 2022)

• Record Type: Journal Article
• Authors: Kelsey, L; Sullivan, M; Wiseman, P; Armstrong, P; Chen, R; Brout, D; Davis, T M; Dixon, M; Frohmaier, C; Galbany, L; Graur, O; Kessler, R; Lidman, C; Möller, A; Popovic, B; Rose, B; Scolnic, D; Smith, M; Vincenzi, M; Abbott, T M C; Aguena, M; Allam, S; Alves, O; Annis, J; Bacon, D; Bertin, E; Bocquet, S; Brooks, D; Burke, D L; Carnero Rosell, A; Carrasco Kind, M; Carretero, J; Costanzi, M; da Costa, L N; Pereira, M E S; Desai, S; Diehl, H T; Everett, S; Ferrero, I; Frieman, J; García-Bellido, J; Gruen, D; Gruendl, R A; Gschwend, J; Gutierrez, G; Hinton, S R; Hollowood, D L; Honscheid, K; James, D J; Kuehn, K; Kuropatkin, N; Lewis, G F; Mena-Fernández, J; Miquel, R; Palmese, A; Paz-Chinchón, F; Pieres, A; Plazas Malagón, A A; Raveri, M; Rodriguez-Monroy, M; Romer, A K; Sanchez, E; Scarpine, V; Schubnell, M; Sevilla-Noarbe, I; Suchyta, E; Swanson, M E C; Tarle, G; Tucker, D L; Weaverdyck, N;
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 519:Issue 2(2023)
• Page Start: 3046
• Page End: 3063
• Publication Date: 2022-12-19
• Subjects: surveys – supernovae: general – distance scale – cosmology: observations; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac3711
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: Recent analyses have found intriguing correlations between the colour ( c ) of type Ia supernovae (SNe Ia) and the size of their 'mass-step', the relationship between SN Ia host galaxy stellar mass ( M stellar ) and SN Ia Hubble residual, and suggest that the cause of this relationship is dust. Using 675 photometrically classified SNe Ia from the Dark Energy Survey 5-yr sample, we study the differences in Hubble residual for a variety of global host galaxy and local environmental properties for SN Ia subsamples split by their colour. We find a 3σ difference in the mass-step when comparing blue ( c < 0) and red ( c > 0) SNe. We observe the lowest r.m.s. scatter (∼0.14 mag) in the Hubble residual for blue SNe in low mass/blue environments, suggesting that this is the most homogeneous sample for cosmological analyses. By fitting for c -dependent relationships between Hubble residuals and M stellar, approximating existing dust models, we remove the mass-step from the data and find tentative ∼2σ residual steps in rest-frame galaxy U − R colour. This indicates that dust modelling based on M stellar may not fully explain the remaining dispersion in SN Ia luminosity. Instead, accounting for a c -dependent relationship between Hubble residuals and global U − R, results in ≤1σ residual steps in M stellar and local U − R, suggesting that U − R provides different information about the environment of SNe Ia compared to M stellar, and motivating the inclusion of galaxy U − R colour in SN Ia distance bias correction.