Optical to X-ray SED at 0.47, 1.25 and 3.4 days after the burst trigger (from left to right) and fitted using the two extinction curves that provide excellent fit at all epochs, that is, the SMC and the SN-type (from top to bottom). Squares show the X-ray flux obtained by our analysis while diamonds are the fluxes by Zafar et al. (2010). The hatched area (delimited by dashed lines) indicates the range of intrinsic power-laws consistent with the  ±2σ uncertainty on β_X. The dashed line in the middle shows the power-law resulting from the best-fit slope to the X-ray data at late epochs (β_X = 1.4). The gray shaded areas show the range of intrinsic power-laws consistent with the  ±1σ uncertainty on β_X. The cyan shaded areas show the the power-laws expected from synchrotron emission (for an electron spectral index p ~ 2.1−2.5 and ν_c < ν_X,opt). The colored areas show the optical to X-ray SED best-fit assuming a power-law model with index free to vary within the range β_X ± 2σ (Table 3).