Lyα SB maps around QSO MUSEUM I sample after PSF- and continuum subtraction (see Section 2.5) from 30 Å NBs centered at the peak Lyα wavelength of the nebula. All images show maps with projected sizes of 20″ × 20″ (about 150 kpc x 150 kpc at the median redshift of the sample) centered on the quasar position. In each map, the gray crosshair indicates the location of the quasar. The contours indicate levels of [2, 4, 10, 20, 50] times the SB limit of each observation (see Table C.1).