Recommended reading 
Recent post on astrobites.org about a paper led by a PhD student from our institute.
The Black Hole Tango: Kicks and Spins in Hierarchical Mergers
“The room is large and densely packed. As you twirl across the floor, someone extends their hand, inviting you to dance. The two of you spin around each other, the tension building with every step. As you draw closer and closer, you realize this isn’t a ballroom, and you’re not people. This is outer space, and you and your partner are black holes, spiraling toward one another in one of the most energetic events in the universe: a black hole merger. (…)”
https://astrobites.org/2025/04/07/gw_kicks_impact_bh_spins_in_hierarchical_mergers/