Feedback under the microscope – II. Heating, gas uplift and mixing in

Using a combination of deep (574 ks) Chandra data, XMM–Newton high-resolution spectra and optical Hα+[N II] images, we study the nature and spatial distribution of the multi-phase plasma in M87. Our results provide direct observational evidence of ‘radio-mode ’ active galactic nuclei (AGN) feedback in action, stripping the central galaxy of its lowest entropy gas and therefore preventing star formation. This low entropy gas was entrained with and uplifted by the buoyantly rising relativistic plasma, forming long ‘arms’. A number of arguments suggest that these arms are oriented within 15◦–30 ◦ of our line-of-sight. The mass of the uplifted gas in the arms is comparable to the gas mass in the approximately spherically symmetric 3.8 kpc core, demonstrating that the AGN has a profound effect on its immediate surroundings. The coolest X-ray emitting gas in M87 has a temperature of ∼0.5 keV and is spatially coincident with Hα+[N II] nebulae, forming a multi-phase medium where the cooler gas phases are arranged in magnetized filaments. We place strong upper limits o