Light curve of the afterglow of GRB 151027B at X-rays as observed with Swift/XRT (top), and in the optical–NIR as observed with GROND (no extinction-correction applied), complemented with two measurements by NOT and RATIR (Malesani et al. 2015; Watson et al. 2015). Error bars are plotted, but are mostly smaller than the symbol size. The vertical gray bands mark the time intervals for which the spectral energy distributions have been established (see text for more details, and Fig. 5).