UV brightness divided by electron energy flux as a function of the electron characteristic energy. Panel (a) is using data points when the brightness is between 10 and 100% of the maximum brightness during the interval and panel (b) data points when the brightness is in the upper 66% of the maximum. The “plus” symbols are color-coded according to the different passes indicated in panel (b). The dark red diamonds are 20-point medians. The vertical bars represent 50% of the data points and the horizontal bars represent the energy span of each group of 20 data points. The black curve is a prediction from Gustin et al. (2016).
