http://arxiv.org/abs/2202.12460
The recently discovered peculiar Gamma-ray Burst, GRB 200826A, poses a dilemma for the collapsar model. Although all other characteristics of the burst are consistent with it being a Type II (i.e., collapse of a massive star) event, the observed duration of the event is only approximately one second, which is at odds with the predicted allowable timescale range for a collapsar event. To resolve this dilemma, this Letter proposes that the original burst could be an intrinsically long GRB comprised of a precursor and a main emission (ME) phase. However, the ME phase is missed due to either precession of the jet or the blockage of a companion star, leaving only the precursor observed as a short-duration GRB 200826A. Interestingly, we found that the temporal and spectral properties of GRB 200826A broadly resembled those of the bright precursor observed in GRB 160625B. Furthermore, assuming the prototype burst of GRB 200826A is similar to GRB 160625B, we found that the observer may indeed miss its ME because of geometric effects caused either by jet precession or companion blockage models. Our approach provides a natural explanation for the GRB 200826A-like bursts and agrees with the rarity of those events.
X. Wang, B. Zhang and W. Lei
Mon, 28 Feb 22
28/38
Comments: 6 pages, 6 figures, 1 tables