Key points are not available for this paper at this time.
Gamma-Ray Bursts (GRBs) are traditionally divided to long and short according to their durations (>//1 are most likely Collapsars, (ii) the only short burst with a clear jet break is most likely a Collapsar, indicating our lack of knowledge concerning non-Collapsar beaming (iii) the existence of non-Collapsars with durations up to 10 sec impose new challenges to non-Collapsar models.
Bromberg et al. (Tue,) studied this question.