Constraining the amount of circumstellar matter and dust around Type Ia supernovae through near-infrared echoes

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 nonstandard 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 (M) over dot less than or similar to 10(-8) - 10(-7) M-circle dot yr(-1) (for the wind velocity of similar to 10 km s(-1)) is obtained for a mass-loss rate from a progenitor up to similar to 0.01 pc, and (M) over dot less than or similar to 10(-7) - 10(-6) M-circle dot yr(-1) up to similar to 0.1 pc.