SNe and GRBs

On my first day in Heidelberg, I attended a colloquium talk by Maryam Modjaz (NYU), about exploding stars. She has very nice results on the metallicities of the environments (galaxy hosts) of supernovae and gamma-ray bursts. She can show that the type Ic broad-lined supernovae are different in chemical environments than the type Ic normal supernovae, and she can show that the SNe associated with GRBs are Ic broad-lined. So the non-GRB type Ic broad-lined supernovae are very likely the counterparts of off-axis gamma-ray bursts. The gamma-ray bursts without gamma rays! This is exciting, because it will bolster the model for GRBs and constrain the beaming.