The Dark Energy Survey Supernova Program results: Type Ia Supernova brightness correlates with host galaxy dust
Creators: name: Meldorf, Cole
name: Palmese, Antonella
name: Brout, Dillon
name: Chen, Rebecca
name: Scolnic, Daniel
name: Kelsey, Lisa
name: Galbany, Lluís
name: Hartley, Will
name: Davis, Tamara
name: Drlica-Wagner, Alex
name: Vincenzi, Maria
name: Annis, James
name: Dixon, Mitchell
name: Graur, Or
name: Kim, Alex
name: Lidman, Christopher
name: Möller, Anais
name: Nugent, Peter
name: Rose, Benjamin
name: Smith, Mathew
name: Allam, Sahar
name: Diehl, H. Thomas
name: Tucker, Douglas
name: Asorey, Jacobo
name: Calcino, Josh
name: Carollo, Daniela
name: Glazebrook, Karl
name: Lewis, Geraint
name: Taylor, Georgina
name: Tucker, Brad E.
name: Aguena, Michel
name: Andrade-Oliveira, Felipe
name: Bacon, David
name: Bertin, Emmanuel
name: Bocquet, Sebastian
name: Brooks, David
name: Burke, David
name: Carretero, Jorge
name: Kind, Matias Carrasco
name: Castander, Francisco Javier
name: Costanzi, Matteo
name: da Costa, Luiz
name: Desai, Shantanu
name: Doel, Peter
name: Everett, Spencer
name: Ferrero, Ismael
name: Friedel, Douglas
name: Frieman, Josh
name: Garcia-Bellido, Juan
name: Gatti, Marco
name: Gruen, Daniel
name: Gschwend, Julia
name: Gutierrez, Gaston
name: Hinton, Samuel
name: Hollowood, Devon L.
name: Honscheid, Klaus
name: James, David
name: Kuehn, Kyler
name: March, Marisa
name: Marshall, Jennifer
name: Menanteau, Felipe
name: Miquel, Ramon
name: Morgan, Robert
name: Paz-Chinchon, Francisco
name: Pereira, Maria Elidaiana da Silva
name: Sanchez, Eusebio
name: Scarpine, Vic
name: Sevilla, Ignacio
name: Suchyta, Eric
name: Tarle, Gregory
name: Varga, Tamas Norbert
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Cosmological analyses with type Ia supernovae (SNe Ia) often assume a single empirical relation between color and luminosity ($β$) 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 modeling of galaxy properties to characterize dust parameters (dust attenuation $A_V$, and a parameter describing the dust law slope $R_V$) for the Dark Energy Survey (DES) SN Ia host galaxies using the publicly available \texttt{BAGPIPES} code. Utilizing optical and infrared data of the hosts alone, we find three key aspects of host dust that impact SN Ia cosmology: 1) there exists a large range ($\sim1-6$) of host $R_V$ 2) high stellar mass hosts have $R_V$ on average $\sim0.7$ lower than that of low-mass hosts 3) there is a significant ($&gt;3σ$) correlation between the Hubble diagram residuals of red SNe Ia that when corrected for reduces scatter by $\sim13\%$ and the significance of the ``mass step'' to $\sim1σ$. These represent independent confirmations of recent predictions based on dust that attempted to explain the puzzling ``mass step'' and intrinsic scatter ($σ_{\rm int}$) in SN Ia analyses. We also find that red-sequence galaxies have both lower and more peaked dust law slope distributions on average in comparison to non red-sequence galaxies. We find that the SN Ia $β$ and $σ_{\rm int}$ both differ by $&gt;3σ$ when determined separately for red-sequence galaxy and all other galaxy hosts. The agreement between fitted host-$R_V$ and SN Ia $β$ \&amp; $σ_{\rm int}$ suggests that host dust properties play a major role in SN Ia color-luminosity standardization and supports the claim that SN Ia intrinsic scatter is driven by $R_V$ variation.
description: 22 pages. Submitted to MNRAS