Intensity measured at the spectral position corresponding to an apparent velocity of 38 km s⁻¹ into the red wing of the Si IV 1394 Å line for each of the 18 rasters sampled during the 21 May 2015 observing sequence. The blue contours over-laid highlight regions where increased intensity (above 40 DN) was detected at the spectral position corresponding to an apparent velocity of 57 km s⁻¹. The FOV of this plot corresponds to the white box over-laid on Fig. 7.