Relative (left panels) and absolute (right panels) vbroad − V sin i residuals plotted as a function of the T_eff error made during the selection of the template spectrum. V sin i stands for the projected rotational velocity adopted to construct the simulation, and vbroad is the estimate provided by the pipeline. Different V sin i (see the legend and colour -coding) and ‘true’ T_eff estimates are considered. In the left panels, the blue hatches identify the domain in which the errors are within 10% of the expected value.