Time history of the >100 MeV flux from ≤10° of the Sun revealing the 2014 Sep. 01 LAT event. Vertical dashed lines show the estimated soft X-ray start and end times from the SAX instrument on MESSENGER that directly observed the flare. The inset shows 1-min accumulation LAT flux data points and arbitrarily scaled 100–300 keV count rates observed by Fermi/GBM. The dashed curve shows the 1–4 keV time profile observed by the SAX instrument. The vertical solid arrow depicts our estimate of the CME onset from inspection of SDO/AIA images and the type II radio emission began about 3 min later. The derivative of the 1–4 keV emission plotted as the thin solid curve is an estimate of the hard X-ray time profile at the flare site.