Radiation of massive gravitation

The radiation problem in massive and massless linear Einstein gravitation is analyzed for mass discontinuities in the limit of vanishing graviton mass m. It is found that in this limit: (i) the radiation into the massive modes of helicity ±2 becomes equal to 3/4 of the total massless Einstein radiation, (ii) the radiation into the massive modes of helicity ±1 tends to zero, and (iii) the radiation into the massive helicity-0 mode stays nonzero and is model-dependent. Two models illustrate this: (i) An oscillating point mass radiates for m→0 into the modes of helicity ±2 and 0, and its total radiation approaches in this limit the massless Einstein radiation; (ii) a pulsar radiates for m→0, but only into the helicity-0 mode: Birkhoff's theorem is broken in linear massive gravitation. It is also broken in massive Maxwell theory, but holds in massless Maxwell theory.