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 broadband colors. In particular, we show that stripped-core SNe (i.e., hydrogen-deficient core-collapse events, spectroscopically defined as SNe Ib and 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 multiband 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, multi-epoch 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.