Illustration of the CCF activity parameters measured in this work. We plotted a typical CCF of an M dwarf (black dots) and the best Gaussian fit (red dashed line) together with the FWHM and contrast derived from the fit (left). We also plotted the bisector of the CCF (grey diamonds) and a zoom to the central region of the CCF to show the bisector shape (right). We indicate the top and bottom regions used to compute the BIS.