ICCF for the FeII emission using different FeII templates (KDP15 and VW01). Left panel: The ICCF for the FeII templates KDP15, KDP15–blue wing, and VW01 without the long-term subtraction (dashed lines). By subtracting the long-term trend from the continuum and line-emission light curves, the ICCF becomes asymmetric with respect to zero (solid lines) and the time-delay peak between 450 and 750 days can be identified, especially for the blue-wing part of the KDP15 template. Right panel: The ICCF for all the three considered cases (KDP15, KDP15–blue wing, VW01) in the interval between 450 and 750 days in the observer’s frame. For the best-fitting KDP15 template, the cross-correlation peak is at ∼600 days. See Table 4 for the summary of the peak and the centroid values (last three rows).