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The Progenitor and Central Engine of a Peculiar GRB 230307A

2024; IOP Publishing; Volume: 962; Issue: 2 Linguagem: Inglês

10.3847/2041-8213/ad22e2

2041-8213

Zhao-Wei Du, Hou-Jun Lü, Yong Yuan, Xing Yang, En‐Wei Liang,

Astrophysical Phenomena and Observations

Abstract Recently, a lack of supernova-associated with long-duration gamma-ray burst (GRB 230307A) at such a low redshift z = 0.065, but associated with a possible kilonova emission, has attracted great attention. Its heavy element nucleosynthesis and the characteristic of soft X-ray emission suggest that the central engine of GRB 230307A is a magnetar that is originated from a binary compact star merger. The calculated lower value of ε ∼ 0.05 suggests that GRB 230307A seems to have an ambiguous progenitor. The lower value of f eff = 1.23 implies that GRB 230307A is not likely to be from the effect of “tip of iceberg.” We adopt the magnetar central engine model to fit the observed soft X-ray emission with varying efficiency and find that the parameter constraints of the magnetar falls into a reasonable range, i.e., B < 9.4 × 10 15 G and P < 2.5 ms for Γ sat = 10 3 , and B < 3.6 × 10 15 G and P < 1.05 ms for Γ sat = 10 4 . Whether the progenitor of GBR 230307A is from the mergers of neutron star–white dwarf (NS–WD) or neutron star–neutron star (NS–NS) remains unknown. The difference of GW radiation between NS–NS merger and NS–WD merger may be a probe to distinguish the progenitor of GRB 230307A-like events in the future.