X-ray light curve of 4U 1907+09. Upper panel: Light curve in the 2–20 keV band as observed by MAXI near the IXPE observations. We also present the folded orbital light curve for MAXI data after MJD 59000 based on the ephemerides from in’t Zand et al. (1998), displayed in light orange, with its width representing flux uncertainties. Note that the folded orbital light curve uses the right-hand axis to emphasize its shape. Lower panel: Combined light curve of 4U 1907+09 from all three DUs of IXPE, with a time resolution of 100 s. The duration of the three flares observed by IXPE is indicated by cyan stripes.