In this paper I put forward a model in which GRB980425 is both associated with SN1998bw and is also a standard canonical ( long ; \sim seconds ) gamma-ray burst .
Herein it is argued that if gamma-ray bursts are relativistic jets with the fastest moving material at the core , then the range of observed jet inclinations to the line-of-sight produces a range in the observed properties of GRBs , i.e .
the lag-luminosity relationship .
In particular , if the jet inclination is high enough , the observed emitter will move slowly enough to render relativistic beaming ineffective , thus distinguishing the jet from apparent isotropic emission .
Thus we expect a break in the lag-luminosity relationship .
I propose that GRB980425 defines that break .
The position of this break gives important physical parameters such as the Lorentz factor ( \gamma _ { max } \sim 1000 ) , the jet opening angle ( \sim 1 degree ) , and thus the beaming fraction ( \sim 10 ^ { -4 } ) .
Estimates of burst rates are consistent with observation .
If correct , this model is evidence in favor of the collapsar mode as the progenitor of cosmological , long gamma-ray bursts .