Expanded view of the delay of the GROND K_s-band light curve (open black symbols with error bars) with respect to the KW light curve (red line). In blue and green we show the shifted (−290 s) and stretched (time axis divided by 1.11) GROND K_s-band light curve, respectively. The black dashed curve at the bottom is the KW highest energy channel G3 (at a factor 3 stretched intensity scaling).