A Sample of Dust Attenuation Laws for DES Supernova Host Galaxies

J. Duarte , S. González-Gaitán , A. Mourao , A. Paulino-Afonso , P. Guilherme-Garcia , J. Aguas , L. Galbany , L. Kelsey , D. Scolnic , M. Sullivan , D. Brout , A. Palmese , P. Wiseman , A. Pieres , A.A. Plazas Malagón (1) , A. Carnero Rosell (1) , C. To , D. Gruen , D. Bacon , D. Brooks , D.L. Burke , D.W. Gerdes , D.J. James , D.L. Hollowood , D. Friedel , E. Bertin , E. Suchyta , E. Sanchez , F. Paz-Chinchón , G. Gutierrez , G. Tarle , H.T. Diehl , I. Sevilla-Noarbe , I. Ferrero , J. Carretero , J. Frieman , J. de Vicente , J. García-Bellido , K. Honscheid , K. Kuehn , M. Gatti , M. Raveri , M.E.S. Pereira , M. Rodriguez-Monroy , M. Smith , M. Carrasco Kind , M. Costanzi , M. Aguena , N. Kuropatkin , N. Weaverdyck , O. Alves , P. Doel , P. Melchior (1) , R. Miquel , R.A. Gruendl , S.R. Hinton , S. Bocquet , S. Desai , S. Everett , T.M. Davis , V. Scarpine

1 IAP - Institut d'Astrophysique de Paris

Type Ia supernovae (SNe Ia) are useful distance indicators in cosmology, provided their luminosity is standardized by applying empirical corrections based on light-curve properties. One factor behind these corrections is dust extinction, accounted for in the color-luminosity relation of the standardization. This relation is usually assumed to be universal, which could potentially introduce systematics into the standardization. The ``mass-step'' observed for SNe Ia Hubble residuals has been suggested as one such systematic. We seek to obtain a completer view of dust attenuation properties for a sample of 162 SN Ia host galaxies and to probe their link to the ``mass-step''. We infer attenuation laws towards hosts from both global and local (4 kpc) Dark Energy Survey photometry and Composite Stellar Population model fits. We recover a optical depth/attenuation slope relation, best explained by differing star/dust geometry for different galaxy orientations, which is significantly different from the optical depth/extinction slope relation observed directly for SNe. We obtain a large variation of attenuation slopes and confirm these change with host properties, like stellar mass and age, meaning a universal SN Ia correction should ideally not be assumed. Analyzing the cosmological standardization, we find evidence for a ``mass-step'' and a two dimensional ``dust-step'', both more pronounced for red SNe. Although comparable, the two steps are found no to be completely analogous. We conclude that host galaxy dust data cannot fully account for the ``mass-step'', using either an alternative SN standardization with extinction proxied by host attenuation or a ``dust-step'' approach.

Domaines: Astrophysique [astro-ph]

J. Duarte, S. González-Gaitán, A. Mourao, A. Paulino-Afonso, P. Guilherme-Garcia, et al.. A Sample of Dust Attenuation Laws for DES Supernova Host Galaxies. Astronomy and Astrophysics - A&A, 2023, 680, pp.A56. ⟨10.1051/0004-6361/202346534⟩. ⟨hal-03894429⟩