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 $\frac{3}{4}$ 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 $m\to 0$ 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 $m\to 0$, 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.