The Blandford–Znajek Process in scalar Gauss–Bonnet and dynamicalChern–Simons gravity

The origin of the energy behind the observed relativistic jets in several accreting objects has been, so far, best explained by the Blandford–Znajek process. Since this process depends on astrophysics (through the magnetosphere) and the theory of gravity (through the exterior black hole spacetime metric), studying its observational consequences may provide another way to learn about gravity in the strong-field regime. How is the Blandford–Znajek process modified in quadratic gravity theories? In this talk, I will show analytical solutions to the Blandford–Znajek process in two well-motivated quadratic gravity theories: scalar Gauss–Bonnet and dynamical Chern–Simons. The mechanism was found assuming the split-monopole configuration and under the small-coupling and slow-rotation approximations. I will finish by comparing our results with the general relativity prediction and discussing what they imply to tests of quadratic gravity theories through the observations of active galactic nuclei.