  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. These properties are similar to those of GRB 060614, and
suggest that the progenitor of GRB 211227A is not favored to be associated with
the death of massive stars. Hence, we propose that GRB 211227A originates from
a compact star merger. Calculating pseudo-kilonova emission for this case by
adopting the typical parameters, we find that any associated pseudo-kilonova is
too faint to be detected. If this is the case, it explains naturally the
characteristics of the prompt emission, the lack of SN and kilonova emission,
and the large physical offset from the galaxy center.

High Energy Astrophysical Phenomena