AGN on the Beach

Feedback (large scales and clusters)

Losing the feedback-feeding loop of the radio galaxy 3C 84

Tom Oosterloo

 Th, 11:45 ! Livein  Palazzo Santa Chiarafor  15min

Gas accretion by a galaxy’s super massive black hole (SMBH) and the energetic feedback by the accreting active galactic nucleus (AGN) on the gas around it are two tightly intertwined processes. Observations of galaxy clusters have shown how plasma jets emitted by the AGN heat the intracluster medium, preventing cooling of the cluster gas and thus the infall of this gas onto the SMBH. However, observations have also shown that rising plasma bubbles, inflated by the jets, instead also induce local cooling of the cluster gas, leading to filaments of cold gas. The fate of these filaments is unclear, but it has been suggested they may feed the AGN activity. We present results of re-processed CO(2-1) ALMA observations of the molecular gas in NGC 1275, the central galaxy of the Perseus cluster hosting the radio-loud AGN 3C 84. These data show, for the first time, in great detail how kpc-sized cold gas filaments resulting from jet-induced cooling of cluster gas are flowing onto the circumnuclear accretion disc of the SMBH, showing that the cooled gas does indeed feed the AGN. These results complete our view of the feedback loop of how an AGN can impact on its surroundings and how the effects from this impact maintain the AGN activity.

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