Ultra Long Gamma-Ray Bursts from the collapse of Blue Super Giant stars: an end-to-end simulation

Understand

Ultra-long gamma ray bursts (ULGRBs) are a distinct class of GRBs characterized by durations of several thousands of seconds, about two orders of magnitude longer than those of standard long GRBs (LGRBs).

• The driving engine of these events has not been uncovered yet, and ideas range from magnetars, to tidal disruption events, to extended massive stars, such as blue super giants (BSG).
• BSGs, a possible endpoint of stellar evolution, are attractive for the relatively long free-fall times of their envelopes, allowing accretion to power a long-lasting central engine.
• At the same time, their large radial extension poses a challenge to the emergence of a jet.