Spin misalignment of black hole binaries from young star clusters: implications for the origin of gravitational waves events

Understand

Recent studies indicate that the progenitors of merging black hole (BH) binaries from young star clusters can undergo a common envelope phase just like isolated binaries.

• If the stars emerge from the common envelope as naked cores, tidal interactions can efficiently synchronize their spins before they collapse into BHs.
• Contrary to the isolated case, these binary BHs can also undergo dynamical interactions with other BHs in the cluster before merging.
• The interactions can tilt the binary orbital plane, leading to spin-orbit misalignment.