Black Hole-Neutron Star Coalescing Binaries

Coalescing black hole–neutron star binaries have been invoked as possible progenitors of short gamma-ray bursts and are also among the most promising gravitational wave sources to be detected by ground-based laser interferometers. When the star is disrupted by tidal interactions before reaching the innermost stable circular orbit, the gravitational wave signal emitted by the system is expected to exhibit a cutoff frequency which is a distinctive feature of the waveform. We evaluate this frequency for several equations of state, describing the matter inside the neutron star, and combinations of the binary parameters. We show that, if this frequency will be found in a detected gravitational wave, it will provide valuable information on the behavior of matter in the stellar core