2016AcA....66..347B

We have studied the future evolution of a recently discovered ULX source P13 in NGC 7793. This source was shown to contain a 5-15 M_☉ black hole and a massive 18-23 M_☉ B9Ia companion on a 64 day orbit. For low black hole mass (5-10 M_☉) and high companion mass >=20 M_☉ the binary is predicted to initiate a common envelope evolution in near future and significantly decrease the orbital separation (6 hr orbit). This leads to a high probability (≃70%) of the system surviving a supernova explosion that will form a neutron star out of the companion. About one third of the surviving BH-NS systems will merge within Hubble time and be a source of high frequency gravitational radiation. We estimate that the chances of detection of BH-NS systems with Advanced LIGO/Virgo that form via P13-evolutionary channel are at the level of 0.1 yr^–1 with wide range of allowed probability 0/0.6 yr^–1. This is the fourth empirical estimate of BH-NS merger rate.