The Role of Angular Momentum and Cosmic Censorship in the (2+1)-Dimensional Rotating Shell Collapse

Understand

We study the gravitational collapse problem of rotating shells in three-dimensional Einstein gravity with and without a cosmological constant.

• Taking the exterior and interior metrics to be those of stationary metrics with asymptotically constant curvature, we solve the equations of motion for the shells from the Darmois-Israel junction conditions in the "co-rotating" frame.
• We study various collapse scenarios with "arbitrary" angular momentum for a variety of geometric configurations, including anti-de Sitter, de Sitter, and flat spaces.
• We find that the collapsing shells can form a BTZ black hole, a three-dimensional Kerr-dS spacetime, and an horizonless geometry of point masses under certain initial conditions.