Converging to the wrong answer: robustness of theory-specific gravitational wave tests of GR

When using Bayesian inference on gravitational wave data to test specific modified theories, one must ensure that the parameter space has been thoroughly explored so that the high likelihood regions have all been identified. Degeneracies between modified theory coupling constants (especially when there are more than one) and astrophysical parameters (like masses and spins) can mislead one to believe a thorough exploration has been accomplished. We will here describe a gravitational wave test of a particular modified theory of gravity, Einstein-æther theory, and the challenges that arise when trying to constrain the parameters of this theory. We will also describe a method to overcome such challenges to reach robust conclusions.