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Journal Club


"Giant Lobes in Radio and Starforming Galaxies As Sources of High-Energy Emission and Particles"

Ł. Stawarz (Institute of Space and Astronautical Science JAXA)

In this talk I will review the most recent observations of giant lobes in a few nearby radio galaxies such as Centaurus A or Centaurus B, as well as in starforming systems such as Circinus or Milky Way ("Fermi Bubbles"), at X-ray and gamma-ray frequencies. I will discuss the pressure balance within these structures, new evidence for a thermal gas mixed with the relativistic plasma within the lobes, and a need for a continuous acceleration of gamma-ray emitting electrons. I will argue that the structure of the extended lobes in all these systems is highly inhomogeneous and non-uniform, with magnetic reconnection and turbulent acceleration processes continuously converting magnetic energy to the internal energy of the plasma particles, leading to possibly significant spatial and temporal variations in the plasma beta parameter around the volume-averaged equilibrium condition beta ~1.