Upper: emission measures computed from AIA 131 Å and IRIS Fe xxi at 11 MK for the first flare. The white box is the region over which we compare EMs in the panels below. Bottom: pixel-by-pixel and row-by-row EMs across the white box region, starting from the upper left. The black line is the Fe xxi EM, and the red line is the 131 Å EM. The +’s indicate those pixels where the Fe xxi emission is higher, and the ×’s mark the selected pixels shown in Fig. 15.