Action space (normalized to the sum of the three actions of motion, J_tot) of Gaia RVS stars with calibrated [Fe/H] < −0.55, along with a zoom-in of the area that we use to select our thin disc sample. The x axis displays the normalized angular momentum, which is equivalent to the azimuthal action of motion and the y axis the normalized difference of vertical action and radial action. Their mean uncertainties are displayed in black on the top right corner.