Optical light curves of the type Ia supernovae SN 1990N and SN 1991T

Abstract

We present UBV RI light curves for the bright Type Ia supernovae SN 1990N in NGC 4639 and SN 1991T in NGC 4527, based on photometry gathered in the course of the Cala n/Tololo supernova program. Both objects have well-sampled light curves starting several days before maximum light and spanning well through the exponential tail. These data supersede the preliminary photometry published by Leibundgut et al. and Phillips et al. The host galaxies for these supernovae have (or will have) accurate distances based on the Cepheid period-luminosity relationship. The photometric data in this paper provide template curves for the study of the general population of Type Ia supernovae and accurate photometric indices, needed for the Cepheid-supernova distance scale.