Median-combined residuals of the PSF subtraction for HIP 65426 (top left), PZ Tel (top right), HD 206893 (bottom left), and β Pic (bottom right). Images are ordered for each target from top to bottom by the central wavelength of the filters. For each object, left column: regular residuals of the PSF subtraction, right column: residuals with the best-fit negative PSF template injected. The color scale is set by the maximum pixel value of each object and filter combination and adjusted by a factor −0.3 of the peak flux for the lower limit. The pixel values within the solid circles (at the positions of the companions) were minimized for the flux estimation while the noise was estimated from the area indicated by the dashed circles (see Sect. 3.3.1 for details). North and east are in upward and leftward direction, respectively, in all images.