Late light curves of normal type Ia supernovae

摘要

We present late-epoch optical photometry (BVRI) of seven normally luminous and superluminous Type Ia supernovae: SN 2000E, SN 2000ce, SN 2000cx, SN 2001C, SN 2001V, SN 2001bg, and SN 2001dp. The photometry of these objects was obtained using a template subtraction method to eliminate galaxy light contamination during aperture photometry. We show the optical light curves of these supernovae out to epochs of up to similar to 640 days after the explosion of the supernova. We show a linear decline in these data during the epoch of 200-500 days after explosion, with the decline rate in the B, V, and R bands equal to about 1.4 mag per 100 days, but the decline rate of the I-band is much shallower at 0.94 mag per 100 days.