Supernovae and gamma-ray burst connection

I review the status of the Supernova/Gamma-Ray Burst connection. Two decades of observations have established that long-duration Gamma-ray Bursts are associated with very energetic SNe-Ib/c. These SN explosions are produced by the gravitational collapse of Wolf–Rayet progenitors, with masses on the main sequence, between 30–50 $M{\odot}$. Current measurements provide a GRB/SNe-Ibc ratio in the range $\sim$0.02–1.5$\%$, so GRBs are very rare events, even when compared with the SN frequency. There is a minority fraction of long-duration GRBs with no accompanying SN that are likely produced during the merging of neutron star or white dwarf neutron star merger.