Formation of X-ray cavities by the magnetically dominated jet-lobe system in a galaxy cluster

We present cosmological magnetohydrodynamic simulations of the formation of a galaxy cluster with magnetic energy feedback from an active galactic nuclei (AGNs). We demonstrate that X-ray cavities can be produced by the magnetically dominated jet-lobe system that is supported by a central axial current. The cavities are magnetically dominated, and their morphology is determined jointly by the magnetic fields and the background cluster pressure profile. The expansion and motion of the cavities are driven initially by the Lorentz force of the magnetic fields, and the cavities only become buoyant at late stages (>500 Myr). We find that up to 80%-90% of the injected magnetic energy goes into doing work against the hot cluster medium, heating it, and lifting it in the cluster potential.