SXS Collaboration's video: Event horizon for equal mass inspiral BBH in two coordinate systems

Event horizon for an equal mass binary black hole system where the black holes are initially in a circular inspiral, in two different coordinate systems. The top row shows the coordinate system used to merge the black holes, and the bottom row shows another coordinate system. The two are related with a simple coordinate transformation where the time coordinate satisfies t' = t + Gaussian. The first half of the video shows the event horizon surfaces, where orange represents the true event horizon, and translucent purple represents "future generators" of the horizon. The second half of the video shows a zoomed in spatial cut through the middle of the event horizon, showing that we are able to find a toroidal topology in this binary with an appropriate coordinate system. Another video zooming into this surface is found here: https://www.youtube.com/watch?v=CeNP5NyW0z4 A video reslicing this system into one where a "baby" event horizon spawns, see here: https://youtu.be/p4MTsCDtHMM For more information about the binary or the methodology, please see our website or our paper https://www.black-holes.org/for-researchers/event-horizon-topologies