Gamma-ray burst jets in supernovae

We review the current observational status and theoretical interpretations for the class of broad lines type Ic supernovae. They are characterized by fast photospheric expansion and lack of H and He absorption. They have a larger than normal energy budget, suggesting that they are powered or, at least, augmented by a central engine, like a magnetar or an accreting black hole. There appears therefore to be a link between these supernovae and long-duration gamma-ray bursts. However, its nature has not been satisfactorily demystified.