Using Rest-Frame Optical and NIR Data from the RAISIN Survey to Explore the Redshift Evolution of Dust Laws in SN Ia Host Galaxies

We use rest-frame optical and near-infrared (NIR) observations of 42 Type Ia supernovae (SNe Ia) from the Carnegie Supernova Project at low-z and 37 from the RAISIN Survey at high-z to investigate correlations between SN Ia host galaxy dust, host mass, and redshift. This is the first time the SN Ia host galaxy dust extinction law at high-z has been estimated using combined optical and rest-frame NIR data (YJ-band). We use the BayeSN hierarchical model to leverage the data’s wide rest-frame wavelength range (extending to ∼1.0–1.2 μm for the RAISIN sample at 0.2 ≲ z ≲ 0.6). By contrasting the RAISIN and CSP data, we constrain the population distributions of the host dust RV parameter for both redshift ranges. We place a limit on the difference in population mean RV between RAISIN and CSP of −1.16 < Δμ(RV) < 1.38 with 95% posterior probability. For RAISIN we estimate μ(RV) = 2.58 ± 0.57, and constrain the population standard deviation to σ(RV) < 0.90 [2.42] at the 68 [95]% level. Given that we are only able to constrain the size of the low- to high-z shift in μ(RV) to ≲ 1.4 – which could still propagate to a substantial bias in the equation of state parameter w – these and other recent results motivate continued effort to obtain rest-frame NIR data at low and high redshifts (e.g. using the Roman Space Telescope).