Observational consequences of a jet-driven supernova (SN) explosion model are
presented. The results are compared in detail with optical observations of SN
1998bw associated with a Gamma-Ray Burst. It is shown that the jet model is
able to reproduce virtually all the optical observations available for this SN,
although a spherical model fails to explain some of observed features. Because
of the viewing angle effect, the required kinetic energy of the SN ejecta is
reduced to ~ 2 x 10^{52} erg as compared to that obtained by the previous
spherical model (~ 5 x 10^{52} erg), but this is still much larger than that of
a canonical SN (~10^{51} erg).Comment: 6 pages, 3 figures. Invited talk at "Frascati Workshop 2007:
Multifrequency Behaviour of High Energy Cosmic Sources", 28 May - 2 June,
2007, Vulcano, Italy. To apper in the Chinese Journal of Astronomy and
Astrophysics (ChJAA