Overview of the entire FOV observed. The highlighted contiguous area close to the boundary of the FOV corresponds to the area used as quiet Sun reference, the highlighted area in the penumbra corresponds to what is referred to as the “interior penumbra”. The top panel corresponds to the 538 nm continuum, the right bottom to the COG velocity measured in the same line. Tick marks are at 1′′ intervals. The arrow points in the direction of Sun center. The dark rectangles outline sub-fields shown in Figs. 3 and 4.