(Non-)abelian gauged supergravities in nine dimensions

We construct five different two-parameter massive deformations of the unique nine-dimensional N=2 supergravity. All of these deformations have a higher-dimensional origin via Scherk-Schwarz reduction and correspond to gauged supergravities. The gauge groups we encounter are SO(2), SO(1, 1)+,R, R+ and the two-dimensional non-abelian Lie group A(1), which consists of scalings and translations in one dimension. We make a systematic search for half-supersymmetric domain walls and non-supersymmetric de Sitter space solutions. Furthermore, we discuss which of the supergravities can be considered as candidate low-energy limits of compactified superstring theory. (author)