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Formation and coalescence of relativistic binary stars: effect of kick velocity

V. M. Lipunov·K. A. Postnov·M. E. Prokhorov
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Abstract

Galactic binary pulsars with different companion types (OB-star, white dwarf (WD), neutron star (NS), black hole (BH), or planet) assuming various phenomenological distributions for kick velocities of newborn NS are studied. The merging rates of relativistic binary stars (NS+NS, NS+BH, BH+BH) dependence on the kick velocity is specially adresed. The BH+BH merging is shown to occur, depending on parameters of BH formation, at a rate of one per 200,000 -- 500,000 years in a Milky Way type galaxy. The NS+NS merging rate $R_{ns}$ is found to be 1 per \sim 3,000 years for zero recoil, and decrease to one per 10,000 years even for the highest kick velocities of 400 km/s. That the merging rates derived from evolutionary calculations are by two order of magnitude higher than those based on binary pulsar statistics only, is suggested to be due to the fact that the observable binary pulsars in pairs with NS form only a fraction of the total number of binary NS systems. The expected detection rate of binary BH by a LIGO-type gravitational wave detector comparable with and even higher than the binary NS merging rate for a wide range of parameters.

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V. M. Lipunov, K. A. Postnov, M. E. Prokhorov. 1997-02-06. Formation and coalescence of relativistic binary stars: effect of kick velocity. https://doi.org/10.1093/mnras%2F288.1.245

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