Late Inspiral and Merger of Binary Black Holes in Scalar-Tensor Theories   of Gravity
  Gravitational wave observations will probe non-linear gravitational interactions and thus enable strong tests of Einstein's theory of general relativity. We present a numerical relativity study of the late inspiral and merger of binary black holes in scalar-tensor theories of gravity. We consider black hole binaries in an inhomogeneous scalar field, specifically binaries inside a scalar field bubble, in some cases with a potential. We calculate the emission of dipole radiation. We also show how these configurations trigger detectable differences between gravitational waves in scalar-tensor gravity and the corresponding waves in general relativity. We conclude that, barring an external mechanism to induce dynamics in the scalar field, scalar-tensor gravity binary black holes alone are not capable of awaking a dormant scalar field, and are thus observationally indistinguishable from their general relativistic counterparts. 
James Healy, Tanja Bode, Roland Haas, Enrique Pazos, Pablo Laguna,   Deirdre M. Shoemaker and Nicol\'as Yunes
gr-qc astro-ph.CO hep-ph