a: visual time evolution of one episode of AGN feedback that starts around t = 350 Myr. Only the dense gas is plotted. The colourmap shows the radial velocity of the gas, with negative values denoting infall, with the background colour set to grey for clarity. The location of the SMBH is marked by a cross, and the contours show the extent of the AGN feedback bubbles produced by the feedback event that starts at t = 323 Myr. b: time evolution of dense gas mass contained in the three categories over the same period of time. Vertical grey lines mark the outputs shown in the top panel.