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In this Letter, we explore the formation of the mass-gap black hole-neutron star (mgBHNS) merger detected in gravitational wave (GW) event, i. e. , GW230529, from the isolated binary evolution channel, and study potential signatures of its electromagnetic signals. By adopting the `delayed' supernova prescription and reasonable model realizations, our population synthesis simulation results can simultaneously match the inferred event rate densities of GW230529-like mgBHNS and total BHNS mergers, as well as the population distribution of the BH mass in BHNS mergers reported by the LIGO-Virgo-KAGRA Collaboration. Thus, we conclude that the recently-discovered mgBHNS merger, GW230529, can be explained through the isolated binary evolution channel. Considering the equation of states of AP4 and DD2, the probabilities that GW230529 can make tidal disruption are 12. 8\% and 63. 2\%, respectively. If GW230529 is a disrupted event, the associated kilonova is predicted to have an apparent magnitude of 23-24\, mag, and hence, can be detected by the present survey projects and LSST. Since GW230529 could be an off-axis event inferred from the GW observation, its associated gamma-ray burst (GRB) might be too dim to be observed by -ray detectors, interpreting the lack of GRB observations. The detection of GW230529 confirms the existence of mgBHNS mergers formed through the isolated binary evolution channel, suggesting that BHNS mergers are still likely to be multimessenger sources that emit GWs, GRBs, and kilonovae. Although mgBHNS mergers account for 60\% cosmological BHNS population, we find that 90\% disrupted BHNS mergers are expected to originate from mgBHNS mergers.
Zhu et al. (Tue,) studied this question.