2015MNRAS.452.3281M

The circumstellar (CS) environment is key to understanding progenitors of Type Ia supernovae (SNe Ia), as well as the origin of a peculiar extinction property towards SNe Ia for cosmological application. It has been suggested that multiple scatterings of SN photons by CS dust may explain the non-standard reddening law. In this paper, we examine the effect of re-emission of SN photons by CS dust in the infrared (IR) wavelength regime. This effect allows the observed IR light curves to be used as a constraint on the position/size and the amount of CS dust. The method was applied to observed near-infrared (NIR) SN Ia samples; meaningful upper limits on the CS dust mass were derived even under conservative assumptions. We thereby clarify a difficulty associated with the CS dust-scattering model as a general explanation for the peculiar reddening law, while it may still apply to a sub-sample of highly reddened SNe Ia. For SNe Ia in general, the environment at the interstellar scale appears to be responsible for the non-standard extinction law. Furthermore, deeper limits can be obtained using the standard nature of SN Ia NIR light curves. In this application, an upper limit of {dot}M \lesssim 10^-8-10^-7  M_☉/yr (for the wind velocity of ∼ 10 km/s) is obtained for a mass-loss rate from a progenitor up to ∼ 0.01 pc, and {dot}M \lesssim 10^-7-10^-6  M_☉/yr up to ∼ 0.1 pc.