I: New constraints on the giant lobe physics and turbulence-driven UHECR acceleration in Centaurus A
Giant lobes of radio galaxies are potential sources of ultra-high energy cosmic rays (UHECRs) detected by large cosmic-ray experiments. Knowledge of the physical conditions -- the energetics, particle content and turbulent state -- in the lobes is vital for understanding high-energy particle acceleration and UHECR production in full. Synthesising the available observational constraints on the physical conditions and particle content in the jets, inner lobes and giant lobes of Centaurus A, we evaluate the feasibility of this object as an UHECR source. We propose a self-consistent model in which hadrons ingested by jets via external entrainment from hot gas and internal entrainment from jet-contained stars contribute to pressure in the giant lobes, and I will show that, to meet the pressure requirements for the lobes, the hadrons must be outstandingly hot. The same 'very hot' temperatures that allow self-consistency between the entrainment calculations and the missing pressure also allow stochastic UHECR acceleration models to work.
Sarka Wykes
Thursday 6 June 2013, 12:00
Location: C4.174