Velocity dispersion analysis plot on Solar Orbiter EPT+HET electron onset times. Horizontal axis corresponds to the inverse unitless velocity of the electrons (1/β = c/v) and the vertical axis shows time. Data points mark the onset times, with horizontal error bars displaying the width of each energy channel and vertical error displaying the uncertainty related to the onset times. The dashed orange line shows a linear fit applied on the selected (solid circles) onset times using orthogonal distance regression (ODR) algorithm. Onset times marked with hollow circles are not considered to the fit for their deviance from the general velocity dispersion trend.