LIE-GROUPS OF CONFORMAL MOTIONS ACTING ON NULL ORBITS

Space-times admitting a 3-dimensional Lie group of conformal motions a cting on null orbits containing a 2-dimensional Abelian subgroup of is ometries are studied. Coordinate expressions for the metric and the co nformal Killing vectors (CKV) are provided (irrespective of the matter content) and then all possible perfect fluid solutions are found, alt hough none of these verify the weak and dominant energy conditions ove r the whole space-time manifold.