Post Here: Definition Topic/Audiences/Exigence > Magnetic Suppression of G-Mode Turbulence in Galaxy Clusters

Audience: This paper is aimed at high energy and plasma astrophysicists interested in the role of magnetic fields in astrophysical atmospheres and specifically how magnetic fields affect the AGN feedback process. I am writing with the professionalism required of the Astrophysical Journal and my writing is aimed at a highly technical audience with sufficient background knowledge in the field.

Context: Galaxy clusters are the most massive "normal" matter structures in the universe. They are composed of a hot atmosphere of plasma (the intracluster medium or ICM) which should have long-ago cooled off, leading to a so-called "cooling catastrophe." Because this cooling catastrophe is not observed, some mechanism must be heating the cluster plasma from within. The conventional explanation for this heating is feedback from supermassive black holes, i.e. active galactic nuclei (AGN) feedback. While AGN feedback can explain the presence of the hot atmosphere, many questions remain as to how the AGN heat the ICM.

Purpose: We use high performance supercomputer simulations to study one way of heating the ICM: g-mode turbulence from AGN-launched jets. Specifically, we use magnetohydrodyanmics (MHD) simulations to investigate how magnetic fields affect the evolution of g-mode turbulence. We find that magnetic fields suppress g-mode turbulence, preventing small-scale heating and the transition of g-modes to turbulence. This work implies that turbulence may not in fact be the means by which AGN heat galaxy clusters, and alternative mechanisms such as sound wave or cosmic ray heating must be investigated in future work.
April 21, 2017 | Unregistered CommenterChristopher J. Bambic