Hawking radiation from the (2 + 1)-dimensional BTZ black holes

Motivated by Robinson-Wilczek’s recent viewpoint that Hawking radiation can be treated as a compensating flux to cancel gravitational anomaly at the horizon of a Schwarzschild-type black hole, we investigate Hawking radiation from the rotating (2+1)-dimensional BTZ black hole in the dragging coordinate system and that from the charged (2+1)-dimensional BTZ black hole via gauge or gravitational anomaly at the horizon. To restore gauge invariance or general coordinate symmetry to hold in the effective theory, one must introduce a gauge current or energy momentum tensor flux to cancel gauge or gravitational anomaly at the horizon. The results show that the values of these compensating fluxes are exactly equal to that of (1+1)-dimensional blackbody radiation at the Hawking temperature.