Program: GN-2007A-Q-112

Twenty years have passed since the peculiar class of Type Ib and Ic supernovae were recognized as core-collapse explosions. However, it is only recently that SNe Ib and Ic have enjoyed a surge of interest thanks to their association with gamma-ray bursts. Today, the most crucial question is whether SNe Ib, Ic, and GRBs arise from similar or distinct progenitor systems (e.g.~single Wolf-Rayet or binary helium stars). It is generally accepted that the presence of Helium differentiates a Type Ib from a Ic, but optical spectroscopy is often ambiguous about the presence of Helium features, due to their intrinsic weakness and line blending. It is therefore not clear if there is a bi-modal or continuous distribution of Helium, a clue to the progenitor classification. Here I propose to ameliorate this problem using near-IR spectroscopy of the unambiguous 1- and 2-micron Helium absorption lines, the strongest Helium features in SN spectra. These observations are part of an on-going long term, multi-wavelength study to understand the progenitors of SNe Ib and Ic and their relation to GRBs.