call this set of objects “Crux Cone".]{}]{} For the further processing we followed the procedures described in @2018arXiv180409366L [Chapter 4.3 and Appendix C, Figs C.1 and C.2] to obtain a stellar sample cleaned from possible artifacts.

First, we required the “visibility periods used" to be equal to or larger than 7 [Eq. (11, ii) in @2018arXiv180409366L], which left us with 19,878 objects. The “unit weight error"-cut [cf. Eq C.1 in @2018arXiv180409366L] removed a considerable portion of dubious entries, and 7,324 sources remained. Instead of the factor of 1.2 in this equation, we used a factor of 1.3 which seems more appropriate to our sample [[and keeps some 40 [[additional]{}]{} stars in the magnitude range $10.0<G<19.5$mag.]{}]{} [Among these 40 stars, 11 (among 1844) will be selected in our final sample. It seems therefore likely that the astrometric parameters for those 11 stars found to be both young and comoving (with a narrow selection, as will be shown below) are correct and those stars should be kept in our analysis. The 1% increase in the statistics has of course no incidence on the conclusion of this paper. ]{} As a next step we applied the “flux excess ratio"-cut [Eq. C.2 in @2018arXiv180409366L] 