Gravity Seminars

Compact objects possessing complicated multipole structure will generally cause precession of the orbital plane when present in a binary system. The most common example of this within general relativity is so-called spin precession, which is caused when the spin angular momentum of the compact object couple to each other, as well as the orbital angular momentum. The precession of the latter of these induces modulations in both the frequency and amplitude of the observed gravitational wave emission of the binary, effects which play a crucial role in parameter estimation. However, if general relativity is not the correct theory of gravity at astrophysical scales and must be modified, or the compact objects have significantly more complicated multipole structure beyond that of a simple pole-dipole, the precession dynamics of the binary will also be modified from that of standard spin precession. Such modifications will necessarily be imprinted in the waveform generated by the precessing binary, opening the door to performing tests of general relativity within the precessing sector of binary dynamics.

In this talk, I will present recent work towards understanding how to use observations of gravitational waves from precessing binaries. As examples, I will discuss two modifications of the standard spin precession paradigm. The first is spin precession in dynamical Chern-Simons gravity, a parity-violating modified theory of gravity that has proven difficult to constrain with non-precessing binaries, and the second is exotic compact objects within general relativity that possess non-axisymmetric violations of the no-hair theorems, such as multipolar boson stars. I will discuss how these two examples allow us to propose an extension of the parameterized post-Einsteinian framework to generic precessing binaries. While work on the first of these two examples is ongoing, I will present projected constraints that one can obtain from this framework on violations of the no-hair theorems with future gravitational wave observations.