Feeding and feedback in radio galaxies and mergers: an X-ray perspective

Abstract

Observations performed in the last decades have shown that supermassive black holes (SMBHs) and cosmic structures are not separate elements of the Universe. While galaxies have sizes roughly ten orders of magnitude larger than SMBHs, black holes would not exist without matter feeding them, and cosmic structures would not be the same without feedback from SMBHs. Powerful winds/jets in active galactic nuclei (AGN) may be the basis of this co-evolution. X-ray observations trace both the cold/feeding and hot/ionized feedback phases. We show the Chandra HETG spectral analysis of two radio galaxies, 3C 390.3 and 3C 120. Complex emission/absorption features are present in the soft X-rays and Fe K band. We detect a hot gas with temperature kT 0.5-1keV from broad ionized Fe L-shell lines which may originate from a kpc scale shocked bubble inflated by the wind/jet. This is reminiscent of supernova bubbles. The shape and strength of the neutral Fe K line suggest that the material feeding the accretion disk, or torus, may be in the form of Compton-thick, clumpy clouds. Such systems may likely be late stage mergers and they allow us to extend the parameter space traced by winds in Seyferts and ULIRGs.