  The Chern-Simons lagrangian density in the space of metrics of a
3-dimensional manifold M is not invariant under the action of diffeomorphisms
on M. However, its Euler-Lagrange operator can be identified with the Cotton
tensor, which is invariant under diffeomorphims. As the lagrangian is not
invariant, Noether Theorem cannot be applied to obtain conserved currents. We
show that it is possible to obtain an equivariant conserved current for the
Cotton tensor by using the first equivariant Pontryagin form on the bundle of
metrics. Finally we define a hamiltonian current which gives the contribution
of the Chern-Simons term to the black hole entropy, energy and angular
momentum.
