Multipole Moments in Einstein's Gravitational Theory

Janis and Newman have proposed definitions of multipole moments of axially symmetric gravitational fields in terms of the initial data on a characteristic surface. This paper extends their definitions to source distributions without symmetry by considering the electromagnetic and linear gravitational fields. The global definition of four-momentum agrees, for sandwich waves, with the objects constructed by Mo/ller and Cornish in their attempts to provide a local definition of four-momentum.