AGN feedback in the FR II galaxy 3C 220.1
Abstract
We present results from a deep (174 ks) Chandra observation of the FR-II radio galaxy 3C 220.1, the central brightest cluster galaxy (BCG) of a kT 4 keV cluster at z=0.61. The temperature of the hot cluster medium drops from 5.9 keV to 3.9 keV at 35 kpc radius, while the temperature at smaller radii may be substantially lower. The central active galactic nucleus (AGN) outshines the whole cluster in X-rays, with a bolometric luminosity of 2.0×1046 erg s-1 (10% of the Eddington rate). The system shows a pair of potential X-ray cavities 35 kpc east and west of the nucleus. The cavity power is estimated within the range of 1.0×1044 erg s-1 and 1.7×1045 erg s-1, from different methods. The X-ray enhancements in the radio lobes could be due to inverse Compton emission, with a total 2-10 keV luminosity of 8.0×1042 erg s-1. We compare 3C 220.1 with other cluster BCGs, including Cygnus A, as there are few BCGs in rich clusters hosting an FR-II galaxy. We also summarize the jet power of FR-II galaxies from different methods. The comparison suggests that the cavity power of FR-II galaxies likely under-estimates the jet power. The properties of 3C 220.1 suggest that it is at the transition stage from quasar-mode feedback to radio-mode feedback.