Extremely efficient mergers of intermediate mass black hole binaries in nucleated dwarf galaxies

Understand

Gravitational waves emitted by merging black holes between $\sim 10^4-10^7~M_\odot$ will be detectable by the Laser Interferometer Space Antenna (LISA) with signal-to-noise ratios of several hundred out to redshift 20.

• Supermassive black hole ($10^7$~M$_{\odot}$ - $10^{10}$~M$_{\odot}$) binary formation, coalescence and merger within massive galaxies is well-studied.
• However, low-to-intermediate mass black holes (IMBHs) are hosted by low-mass and dwarf galaxies; it is not trivial to extrapolate black hole merger timescales to this IMBH binary regime, due to the starkly different host galaxy structure, kinematics, and morphology compared to massive galaxy hosts.
• We perform ultra-high resolution $N$-body simulations to study IMBH dynamics in nucleated dwarf galaxies whose structural parameters are obtained from observations of nearby dwarf galaxies.