Holographic anomaly in 3d f(Ric) gravity

By applying the holographic renormalization method to the metric formalism of f(Ric) gravity in three dimensions, we obtain the Brown-York boundary stress-tensor for backgrounds which asymptote to the locally AdS3 solution of Einstein gravity. The logarithmic divergence of the on-shell action can be subtracted by a non-covariant cut-off independent term which exchanges the trace anomaly for a gravitational anomaly. We show that the central charge can be determined by means of BTZ holography or in terms of the Hawking effect of a Schwarzschild black hole placed on the boundary.