Non-Einstein source effects in massive gravity

Understand

We exhibit novel effects (absent in GR) of sources in massive gravity.

• First, we show that removing its ghost mode forces a field-current identity: The metric's trace is locally proportional to that of its stress tensor; a point source implies a metric singularity enhanced by the square of the graviton's range.
• Second, exterior solutions acquire spatial stress hair--their metric components depend on the interior T_ij.
• Also, in contrast to naive expectations, the Newtonian potential of a source is now determined by both its spatial stress and mass.