$SO(p,q)$-Higgs bundles and Higher Teichmüller components

Some connected components of a moduli space are mundane in the sense that they are distinguished only by obvious topological invariants or have no special characteristics. Others are more alluring and unusual either because they are not detected by primary invariants, or because they have special geometric significance, or both. In this paper we describe new examples of such 'exotic' components in moduli spaces of $SO(p,q)$-Higgs bundles on closed Riemann surfaces or, equivalently, moduli spaces of surface group representations into the Lie group $SO(p,q)$. Furthermore, we discuss how these exotic components are related to the notion of positive Anosov representations recently developed by Guichard and Wienhard. We also provide a complete count of the connected components of these moduli spaces (except for $SO(2,q)$, with $q⩾4$).