Asymptotically flat spacetimes in 3D bigravity
  We report that a class of three-dimensional bimetric theories contain asymptotically flat solutions. These spacetimes can be cast in a set of asymptotic conditions at null infinity which are preserved under the infinite dimensional BMS group. Moreover, the algebra of the canonical generators exhibits a central extension. The possibility that these solutions describe regular black holes is also discussed. 
Hernan A. Gonzalez, Miguel Pino
gr-qc hep-th