Count rate-count rate correlation coefficients between different energy bands for the 10 observations. In each panel, the green star is the XMM-Newton/OM light curve in the 3−6 eV band; the three blue crosses correspond to the XMM-Newton/pn soft X-ray bands: 0.2−0.5 keV, 0.5−1 keV, 1−2 keV; the three red diamonds correspond to the XMM-Newton/pn medium X-ray bands: 2−4 keV, 4−6 keV, 6−12 keV; and the two black triangles correspond to the INTEGRAL/ISGRI hard X-ray bands: 20−60 keV and 60−200 keV. In each panel, the light curves are correlated with the one marked with the vertical dotted lines. We have overplotted the 95% and 99% confidence levels for the significance of the correlation (it corresponds to correlation coefficients of 0.64 and 0.78, respectively, for 10 points) with horizontal dot-dashed and dashed lines, respectively.