GX 13+1 XMM-Newton EPIC pn light curves and hardness ratio (with a bin time of 100.0 s) of Obs. 1 (left panel group) and Obs. 2 (right panel group). In both panel groups, the upper panel shows the light curve in the 0.7 to 4.0 keV energy range, the second panel shows the light curve in the 4.0–10.0 keV energy range, the third panel (in blue) shows the light curve in the total energy range, from 0.7 to 10.0 keV, and the lower panel (in red) shows the hardness ratio between the photon counts in the 4.0–10.0 keV energy range by those in the 0.7–4.0 keV energy range.