A spectral sequence determining the homology of out(Fn) in terms of its mapping class subgroups

We construct a covering of the spine of the Culler-Vogtmann outer space Out(F-n) by complexes of ribbon graphs. By considering the equivariant homology for the action of Out(F-n) on this covering, we construct a spectral sequence converging to the homology of Out(F-n) that has its E-1 terms given by the homology of mapping class groups and their subgroups. This spectral sequence can be seen as encoding all of the information of how the homology of Out(F-n) is related to the homology of mapping class groups and their subgroups.