multiblackholes

Multiblackholes are systems or solutions in which more than one black hole occupies a common region of spacetime. The concept appears in astrophysical contexts as well as in theoretical models within general relativity. In practice, multiblackhole configurations range from bound pairs of black holes to more complex arrangements involving three or more objects.

In astronomy, the most familiar examples are binary black hole systems, formed when galaxies merge and their central black holes sink toward the new galactic center due to dynamical friction. Hierarchical triples and higher-order multiples can arise in dense stellar environments or during successive mergers. Supermassive black hole binaries are of particular interest because their orbital evolution and eventual coalescence emit strong gravitational waves and may influence galactic evolution and accretion activity.

Dynamics of multiblackhole systems are governed by gravity, gravitational radiation, and, when present, interactions with matter and magnetic fields. Binary and higher-order interactions can drive mergers, alter orbital parameters, and produce distinctive gravitational-wave signals. Triple systems may exhibit complex dynamics, including Kozai-Lidov oscillations and possible ejections, depending on masses and separations. Gravitational radiation dominates the final inspiral and merger phase.

Observationally, gravitational waves detected by LIGO and Virgo confirm the existence of merging black holes, primarily binaries. Evidence for wider or more complex multiblackhole systems remains indirect, including periodicities or peculiar emissions in active galactic nuclei and reductions in stellar or gas dynamics. Future instruments like pulsar timing arrays and space-based detectors aim to observe supermassive and intermediate-mass black hole binaries, improving constraints on multiblackhole populations.

See also: binary black hole, triple system, gravitational waves, black hole mergers.