Merging stellar and intermediate-mass black holes in dense clusters: implications for LIGO, LISA and the next generation of gravitational wave detectors

Understand

We study the formation of intermediate-mass ratio inspirals (IMRIs) triggered by the interactions between two stellar black holes (BHs) and an intermediate-mass BH (IMBH) inhabiting the centre of a dense star cluster.

• We exploit $N$-body models varying the IMBH mass, the stellar BH mass spectrum, and the star cluster properties.
• These simulations are coupled with a semi-analytic procedure to characterise the evolution of the remnant IMBH.
• The IMRIs formation probability attains values $\sim 5-50\%$, with larger values corresponding to larger IMBH masses.