Intrinsic color diversity of nearby Type Ia supernovae

Abstract It has been reported that the extinction law for Type Ia supernovae (SNe Ia) may be different from one in Milky Way, but intrinsic color of SNe and dust are observationally mixed. In this study, we examine photometric properties nearby universe (z ? 0.04) to investigate SN extinction. We focus on Branch spectroscopic classification 34 morphological types host galaxies. carefully study distribution their peak colors B ? V, V R color–color diagram, as well excess absolute magnitude deviation stretch-color relation bluest Ia. find which show reddest occur early-type spirals trend holds when divided into sub-types. The becomes close Way like if exclude some peculiar red Broad Line (BL) sub-type Furthermore, two these BLs elliptical galaxies, a less-dusty environment, suggesting diversity BL