Foreground contamination rates per galaxy. Left: foreground contamination rate as a function of Galactic latitude derived from the TRILEGAL Milky Way simulations. The colour encodes the Galactic longitude. To maintain readability, only galaxies with a minimum of 100 YSG candidates are included. Right: empirical cumulative distribution function (ECDF) of the foreground contamination rate. For 75% of the galaxies, fewer than 10% of their YSG candidates are foreground contaminants.