The plot shows stars in one of the Gaia-ESO Milky Way field, GES_MW_142000-050000. Small dots are surrounding stars, while the large dots are stars involved in the calculation of the selection function (see Section 6 for details). Green thin line – a 1-deg (diameter) field-of-view; red dashed line – a 35 arcmin (diameter) field-of-view; blue solid line – final target selection with a 25 arcmin (diameter) field-of-view (i.e. that at FLAMES on VLT).