GRB 191019A: a short gamma-ray burst in disguise from the disk of an active galactic nucleus

Understand

Long and short gamma-ray bursts (GRBs), canonically separated at around 2 seconds duration, are associated with different progenitors: the collapse of a massive star and the merger of two compact objects, respectively.

• GRB 191019A was a long GRB ($T_{90}\sim64$ s).
• Despite the relatively small redshift z=0.248 and HST followup observations, an accompanying supernova was not detected.
• In addition, the host galaxy did not have significant star formation activity.