Warp and flare of the Galactic disc revealed with supergiants by Gaia EDR3

Chrobáková, Ž.; Nagy, R.; López-Corredoira, M.
Bibliographical reference

Astronomy and Astrophysics

Advertised on:
8
2022
Number of authors
3
IAC number of authors
2
Citations
11
Refereed citations
10
Description
Context. The outer Galactic disc contains some features such as the warp and flare, whose origin is still debated. The Gaia data provide an excellent opportunity to probe the Galactic disc at large distances and study these features.
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.
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NGC 2808 Globular Cluster
Milky Way and Nearby Galaxies

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

Martín
López Corredoira