Progenitors and emission mechanisms of merger-driven long GRBs

Determine the progenitor systems and the emission mechanisms responsible for the longer gamma-ray signals observed in merger-driven long-duration gamma-ray bursts, such as GRB211211A and GRB230307A, in order to establish whether these events arise from compact object mergers and to identify the physical process that powers their extended gamma-ray emission.

Background

The paper reports that several recent kilonovae followed long-duration gamma-ray bursts, a surprising development given the conventional association of long GRBs with massive star collapse. This motivates a unified modeling effort to explore diversity and to compare properties across short and long GRB populations.

The origin of the extended gamma-ray emission in these merger-driven long GRBs is uncertain; multiple theoretical explanations have been proposed but remain observationally untested. Resolving the progenitors and mechanisms is essential for understanding how compact-object mergers produce long-lived relativistic outflows.

References

Surprisingly, two of these kilonovae followed long-duration GRBs. The progenitors and/or emission mechanisms driving their longer γ-ray signals remain an unknown, with several observationally untested theories (e.g., Yang et al. 2022; Gottlieb et al. 2023).

— Uniform Modeling of Observed Kilonovae: Implications for Diversity and the Progenitors of Merger-Driven Long Gamma-Ray Bursts (2409.02158 - Rastinejad et al., 3 Sep 2024) in Introduction