XTEJ1550-564 SEDs during the 2003 mini-outburst. Left: comparison between reddened (crosses in the lower part) and dereddened (asterisks in the upper part) optical/NIR SEDs. From optical (right) to IR (left): BVRI JHK_s points. The error bars are also shown and are bigger in the case of the dereddened points owing to the 1.6σ uncertainty on the N_H and then on A_v (see Sect. 3.1). We also show here power law slopes, with spectral indices given in the text. Right: broadband SED. Our ESO/NTT observations taken during the mini-outburst are shown with asterisk symbols, and the data taken during quiescence (K_s flux obtained during our polarimetric run, J and V flux from Orosz et al.2011) are shown with lozenges. All these data are dereddened with A_V = 4.92 mag, and the error bars show the uncertainty on the column density. We also plot the simultaneous X-ray flux/spectrum (Aref’ev et al. 2004), and the ATCA radio fluxes observed during the 2002 outburst, with similar X-ray flux.