Black hole and neutron star mergers in galactic nuclei

摘要: Nuclear star clusters surrounding supermassive black holes (SMBHs) in galactic nuclei contain large numbers of stars, (BHs) and neutron stars (NSs), a fraction which are likely to form binaries. These binaries were suggested triple system with the SMBH, acts as perturber may enhance BH NS mergers via Lidov-Kozai mechanism. We follow-up previous studies, but for first time perform an extensive statistical study BH-BH, NS-NS BH-NS binary by means direct high-precision regularized $N$-body simulations, including Post-Newtonian (PN) terms up order PN2.5. consider different SMBH masses, slopes mass function, semi-major axis eccentricity distributions, spatial distributions find that merger rates decreasing function ranges $\sim 0.17$-$0.52 \ \mathrm{Gpc}^{-3}\ \mathrm{yr}^{-1}$, 0.06$-$0.10 \mathrm{yr}^{-1}$ 0.04$-$0.16 binaries, respectively. However, rate estimate from this channel remains highly uncertain depends on specific assumptions regarding star-formation history supply compact objects. 10\%$--$20\%$ enter LIGO band eccentricities $\gtrsim 0.1$. also compare our results secular approximation, show simulations generally predict larger number mergers. Finally, these events can be observable their electromagnetic counterparts, thus making object especially valuable cosmological astrophysical purposes.