Understanding Long-lived comma Ubiquitous AGN Feedback in Early-type Galaxies

Unlike AGN feedback in galaxy clusters, in which heating and cooling arebalanced at each radius, feedback in earlytype galaxies is often overpoweredand able in principle to heat the galaxy quickly. How to sustain longlivedubiquitous jets in such systems remains a puzzle. If a reservoir of quiescenthot gas were maintained in the vicinity of black hole, however, it may continueto power accretion, leading to continuous energy release from the black hole.RGS analysis of a sample of elliptical galaxies showed indications of suchfeedback in M84. We propose a 380 ks observation of this system with RGS toprobe the dynamics of the gas in the inner few kpc and determine whether it islargerly quiescent (in contrast to the galaxy outskirts) and is indeed in heatingcooling imbalance. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]