P13 an ULX that is a Potential Progenitor of Merging BH-NS System

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.

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Opracowanie rekordu w ramach umowy 509/P-DUN/2018 ze środków MNiSW przeznaczonych na działalność upowszechniającą naukę (2019).