Stellar signal components fitted to the combined HARPS and HARPS-N VPSD (solid gray curve). The dotted red curve shows the photon-noise constant. The dashed curves represent Lorentzian functions for oscillations (purple), rotation and its harmonics (green), and aliases (black), whereas dash-dotted curves represent Harvey functions for granulation (cyan) and supergranulation (blue). The solid black curve is the sum of all components, which was fitted with respect to the binned VPSD (black circles).