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

This is the authors' abstract. We don't add key points for this paper.

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 microns for the RAISIN sample at 0.2 z0.6). 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).