GRB 211227A as a peculiar long gamma-ray burst from compact star merger

Understand

Long-duration gamma-ray bursts (GRBs) associated with supernovae (SNe) are believed to originate from massive star core-collapse events, whereas short-duration GRBs that are related to compact star mergers are expected to be accompanied by kilonovae.

• GRB 211227A, which lasted about 84 s, had an initial short/hard spike followed by a series of soft gamma-ray extended emission at redshift $z=$0.228.
• We performed follow-up observations of the optical emission using BOOTES, LCOGT, and the Lijiang 2.4m telescope, but we detected no associated supernova signature, even down to very stringent limits at such a low redshift.
• We observed the host galaxy within a large error-circle and roughly estimate the physical offset of GRB 211227A as $20.47\pm14.47$ kpc from the galaxy center.