Tests of Gravity Theories Using Supermassive Black Holes

Understand

Scalar-tensor theories of gravity generally violate the strong equivalence principle, namely compact objects have a suppressed coupling to the scalar force, causing them to fall slower.

• A black hole is the extreme example where such a coupling vanishes, i.e.
• black hole has no scalar hair.
• Following earlier work, we explore observational scenarios for detecting strong equivalence principle violation, focusing on galileon gravity as an example.