ON GRAVITATIONAL SHOCK-WAVES IN CURVED SPACETIMES

Some years ago Dray and 't Hooft found the necessary and sufficient co nditions to introduce a gravitational shock wave in a particular class of vacuum solutions to Einstein's equations. We extend this work to c over cases where non-vanishing matter fields and a cosmological consta nt are present. The sources of gravitational waves are massless partic les moving along a null surface such as a horizon in the case of black holes. After we discuss the general case we give many explicit exampl es. Among them are the d-dimensional charged black hole (that includes the 4-dimensional Reissner-Nordstrom and the d-dimensional Schwarzsch ild solution as subcases), the Lt-dimensional De Sitter and anti-De Si tter spaces (and the Schwarzschild-De Sitter black hole), the 3-dimens ional anti-De Sitter black hole, as well as backgrounds with a covaria ntly constant null Killing vector. We also address the analogous probl em for string-inspired gravitational solutions and give a few examples .