Left panel: data/continuum model ratio of the simulated RGS spectra for r = 10^15.75 cm around the region of the Fe UTA complex (15−17 Å, gray area in the spectra) for distinct time steps indicated by the dashed lines on the right. Right panel: slice of the generated light curves from the simulated spectra, which includes the time steps of the spectra in the left. We note that spectra a), c) and d) have approximately the same flux level but show different absorption features, which indicates the dependence of the warm absorber on the flux variation history.