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Abstract

Although being among the closest gamma-ray bursts, GRB 211211A poses
challenges for its classification with partially inconclusive electromagnetic
signatures. In this paper, we investigate four different astrophysical
scenarios as possible progenitors for GRB 211211A: a binary neutron-star
merger, a black-hole--neutron-star merger, a core-collapse supernova, and an
r-process enriched core collapse of a rapidly rotating massive star (a
collapsar). We perform a large set of Bayesian multi-wavelength analyses based
on different models and priors to investigate which astrophysical scenarios and
processes might have been related to GRB 211211A. Our analysis supports
previous studies in which the presence of an additional component, likely
related to $r$-process nucleosynthesis, is required to explain the observed
light curves of GRB 211211A, as it can not solely be explained as a GRB
afterglow. Fixing the distance to about $350~\rm Mpc$, i.e., the distance of
the possible host galaxy SDSS J140910.47+275320.8, we find a statistical
preference for the binary neutron-star merger scenario and estimate the
component masses to be $1.55^{+0.54}_{-0.42} M_{\odot}$ and
$1.34^{+0.25}_{-0.40} M_{\odot}$.