Normalized Stokes q (a) and u (b) parameters, PA (c), PD (d), hardness ratio (e) with the same colors as in Fig. 2, and the count rate (f) as functions of time as observed by IXPE (all three detectors combined in the energy range 2–8 keV). The light curve is binned in ≈200 s. The dashed vertical blue lines separate the observation into five equal time bins of 10.5 h (Bins 1–5). The region highlighted in yellow corresponds to the dip in the light curve (see Sect. 3.1). Uncertainties are reported at the 68% CL.