Polarization Signatures of Relativistic Aberration in Black Hole Jets

Black holes holes and other compact objects are known to produce luminous jets, a number of which have been directly seen in radio observations from Earth. However, the source of black hole jet power remains an open question in astrophysics. In this talk, I will discuss how polarized observations of jets close to the launching point can provide evidence of the Blandford-Znajek (1977) mechanism, a theorized process by which rotational energy of Kerr black holes can be converted into an outward energy flux along dynamical magnetic fields. I will explain explain our process for simulating and interpreting polarized images of jets, and I will focus on the importance of relativistic aberration in controlling the observed signature. In particular, the steepness of the jet collimation profile directly controls whether the jet will produce an azimuthal or radial polarization pattern. These polarimetric signatures can be used by the Event Horizon Telescope to directly test the origin of energy outflow near supermassive black holes.