Comparison of the azimuthal-correlation distributions of electrons from heavy-flavor hadron decays and charged particles measured in the 0--10\% centrality class Pb--Pb collisions and in pp collisions , after the baseline subtraction, for $4 \pt^{\rm e} 12$ \GeVc  and different associated \pt intervals. The statistical (uncorrelated systematic) uncertainties are shown as vertical lines (filled boxes). The uncertainties on the baseline estimation are shown as solid boxes at $\dph \sim -2$ and $5$ rad. The shaded gray area corresponds to the integrated regions in $\dph$ to obtain the NS and AS yield.