Warp and flare of the Galactic disc revealed with supergiants by <i>Gaia</i> EDR3

Context. The outer Galactic disc contains some features such as the warp and flare, whose origin is still debated. Gaia data provide an excellent opportunity to probe at large distances study these features. Aims. We derive density distributions of average (old) whole population supergiants (representative a young population), we use them constrain their flare. By comparing results, how properties phenomena depend on studied population. Methods. used Lucy’s deconvolution method recover corrected star counts function distance, from which distribution. Results. find that have asymmetric warp, reaching maximum amplitude z w = 0.658 kpc minimum ?0.717 distance R [19.5, 20] kpc, almost twice high disc. significant flare population, especially in thick scale height increases h ,thick ? 0.7 , thin 0.3 solar neighbourhood, 2.6 0.6 remote regions Milky Way ( 18 kpc). supergiants’ has only small