Non-compact gaugings from higher dimensions

The N = 8 supergravity theories in four (and five) dimensions with non-compact gauge groups are obtained from eleven- (and ten-)dimensional supergravities in back-grounds with non-compact internal spaces. The SO(p,q) gaugings are obtained by a consistent truncation of the higher-dimensional supergravity in a background that is a warped product of a four- (or five-) dimensional Einstein space with the hyperboloid Hq,p. These backgrounds are solutions of the higher-dimensional field equations precisely when the lower-dimensional supergravity has a SO(p) x SO(q) invariant vacuum solution. The mode analysis and massive spectra in these backgrounds are briefly considered. (author)