Astronomy and Astrophysics
Aims: We derive the density distributions of the average (old) whole population and the supergiants (representative of a young population), and we use them to constrain their warp and flare. By comparing the results, we study how the properties of these phenomena depend on the studied population.
Methods: We used Lucy's deconvolution method to recover corrected star counts as a function of distance, from which we derive the density distribution.
Results: We find that supergiants have an asymmetric warp, reaching a maximum amplitude of zw = 0.658 kpc and minimum amplitude of zw = −0.717 kpc at a distance of R = [19.5, 20] kpc, which is almost twice as high as the amplitude of the whole population of the disc. We find a significant flare of the whole population, especially in the thick disc. The scale height increases from hz,thick ≈ 0.7 kpc and hz, thin ≈ 0.3 kpc in the solar neighbourhood, to hz, thick ≈ 2.6 kpc and hz, thin ≈ 0.6 kpc in the remote regions of the Milky Way (R ≈ 18 kpc). The supergiants' population has only a small flare.
The general aim of the project is to research the structure, evolutionary history and formation of galaxies through the study of their resolved stellar populations, both from photometry and spectroscopy. The group research concentrates in the most nearby objects, namely the Local Group galaxies including the Milky Way and M33 under the hypothesis