UVOT (uvw2,   uvm2,   uvw1,   u,   b,   v) effective areas (against left y-axis) and GROND (g′,   r′,   i′,   z′,   J,   H,   K_s) filter curves (right y-axis), respectively in colored areas. The UVOT effective areas have been obtained from the most recent HEASARC Calibration Database¹. GROND filter curves include all optical components in GROND including the telescope, but exclude the atmosphere. Shown in black lines are template afterglow spectra, from redshifts z = 1, 2, 3, 4.5, 6 to 8 (top left to bottom right). These spectra also differ in their spectral index and rest-frame extinction (amount and reddening law), see e.g. the two synthetic spectra at z = 4.5 and 6, which show a redshifted 2175 Å dust feature. Also the DLAs centered at 121.5 × (1 + z) nm differ in their hydrogen column densities.