Simulating Magnetic fields in AGN jets: Faraday rotation as a probe of environment – Larissa Jerrim
Channel: Herts Research
Date: 05/09/2023

This is a recording of a special talk on 5 Sep 2023 by Larissa Jerrim, visiting from the University of Tasmania. 

Title: Magnetic fields in simulations of AGN jets: Faraday rotation as a probe of environment

Abstract: Active galactic nuclei (AGN) are the most energetic objects in the Universe. They play a key role in galaxy formation and evolution by regulating galaxies and their environments through jet feedback. The problem is interpreting radio observations of AGN jets is challenging due to degeneracies between their physical parameters. Critically, different combinations of jet kinetic power and environment density can produce the same observable radio continuum properties, including apparent size and synchrotron luminosity. This is a major challenge for quantifying jet energetics, and hence AGN feedback.  In this talk, I will present an approach to break this degeneracy by probing the line-of-sight environment with Faraday rotation. I present simulations of three-dimensional relativistic magnetohydrodynamic (RMHD) AGN jets in environments with turbulent magnetic fields. I generate synthetic radio observables and Faraday rotation measures (RMs), then use this information to constrain the jet and environment parameters. I discuss the depolarization properties of my simulated sources and quantify the observability of the RMs. I briefly discuss the range of new opportunities this technique offers, including probing radio galaxy environments and more accurate estimates of the AGN feedback budget.