Tidal deformations of spinning black holes in Bowen-York initial data

Understand

We study the tidal deformations of the shape of a spinning black hole horizon due to a binary companion in the Bowen-York initial data set.

• We use the framework of quasi-local horizons and identify a black hole by marginally outer trapped surfaces.
• The intrinsic horizon geometry is specified by a set of mass and angular-momentum multipole moments $\mathcal{M}_n$ and $\mathcal{J}_n$ respectively.
• The tidal deformations are described by the change in these multipole moments caused by an external perturbation.