A thin disk model for the high efficiency jet in powerful lobe-dominated FRII radio galaxies

We propose a thin accretion disk with magnetically driven winds model to investigate the high jet efficiency phenomenon in lobe-dominated luminous FRII radio galaxies, which was reported by Fernandes et al. (2011) and Punsly (2011). It was found that the temperature of a thin disk with winds was much lower comparing with that of a standard thin disk because the winds take the most of energy released in the disk away, resulting in a much smaller raditive efficiency. Therefore, the jet efficiency can be very high even for conventional jet power. Our model can explain the observations quite well.