Photometric Identification of Young Stripped-Core Supernovae

We present a method designed to identify the spectral type of young (less than ∼ 30 days after explosion) and nearby (z < ∼ 0.05) supernovae (SNe) using their broad-band colors. In particular, we show that stripped-core SNe (i.e., hydrogen deficient core-collapse events, spectroscopically defined as SNe Ib and SNe Ic, including broad-lined SN 1998bw-like events) can be clearly distinguished from other types of SNe. Using the full census of nearby SNe discovered during the year 2002, we estimate the impact that prompt multi-band photometry, obtained by 1 m class telescopes, would have on the early identification of stripped-core events. Combining this new approach with ongoing spectroscopic follow-up programs, one can expect ∼ 20 nearby, stripped-core events to be identified, each year, around, or before, maximum light. Follow-up studies, including prompt, multiepoch optical spectroscopy and spectropolarimetry, as well as radio and X-ray observations, could greatly increase our understanding of these events, and shed new light on their association with cosmological gamma-ray bursts. Subject headings: supernovae: general