Synthetic electron energy distribution functions (eEDFs) sampled along Mariner10 (a)–(d) and BepiColombo (e)–(h) first Mercury flybys in our simulation boxes using northward IMF (left panels) and southward IMF (right panels) conditions. The plots are done using simulation results at time = 14.7R/V_x. The energy ranges and resolutions used to compute the eEDF are the same as those of the instruments PLS (onboard Mariner, top) and MEA1 (onboard BepiColombo, bottom). The horizontal axis shows the time from closest approach (CA) in minutes, and t = 0 is highlighted using vertical red dashed line. On the time axis, we highlight the bow shock and magnetopause crossings obtained by the two spacecraft in situ. These are highlighted using gray areas and vertical black dashed lines. The electron density was obtained by integrating the synthetic eEDF in energy at each given time.