Peak pulse lead time (μs) of various observations plotted against energy (keV) in optical, X-rays and γ-ray energy bands. A constant model is fitted to the data, which is found to be 284.4 μs. The data points shown above cover more than seven orders of magnitude in energy and come from different observations and experiments mentioned in the graph (Kuiper et al. 2003; Rots et al. 2004; Oosterbroek et al. 2008; Abdo et al. 2010; Molkov et al. 2010). Only the central energy corresponding to an individual observation was plotted along with the corresponding lead time measured within the observed energy band.