AGN feedback and iron enrichment in the powerful radio galaxy, 4C+55.16.

ABSTRACT We present a detailed X-ray analysis of 4C+55.16, an unusual and interesting radio galaxy, located at the centre of a cool core cluster of galaxies. 4C+55.16 is X-ray bright ( LX(cluster)∼ 1045 erg s−1), radio powerful, and shows clear signs of interaction with the surrounding intracluster medium (ICM). By combining deep Chandra (100 ks) with 1.4 GHz Very Large Array observations, we find evidence of multiple outbursts from the central active galactic nucleus (AGN), providing enough energy to offset cooling of the ICM ( Pbubbles= 6.7 × 1044 erg s−1). Furthermore, 4C+55.16 has an unusual intracluster iron distribution showing a plume-like feature rich in Fe L emission that runs along one of the X-ray cavities. The excess of iron associated with the plume is around 107 M⊙. The metal abundances are consistent with being solar-like, indicating that both Type Ia supernova and Type II supernova contribute to the enrichment. The plume and southern cavity form a region of cool metal-rich gas, and at the edge of this region, there is a clear discontinuity in temperature (from kT∼ 2.5 to ∼5.0 keV), metallicity (from ∼0.4 to ∼0.8 Z⊙), and surface brightness distribution, consistent with it being caused by a cold front. However, we also suggest that this discontinuity could be caused by cool metal-rich gas being uplifted from the central AGN along one of its X-ray cavities. [ABSTRACT FROM AUTHOR]