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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Globular clusters in the inner Galaxy classified from dynamical orbital criteria

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Perez-Villegas, Angeles [1] ; Barbuy, Beatriz [1] ; Kerber, Leandro O. [2] ; Ortolani, Sergio [3] ; Souza, Stefano O. [1] ; Bica, Eduardo [4]
Total Authors: 6
[1] Univ Sao Paulo, IAG, Rua Matao 1226, Cidade Univ, BR-05508900 Sao Paulo - Brazil
[2] Univ Estadual Santa Cruz, Dept Ciencias Exatas & Technol, Rodovia Jorge Amado Km 16, BR-45662000 Ilheus, BA - Brazil
[3] Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Vicolo Osservatorio 3, I-35122 Padua - Italy
[4] Univ Fed Rio Grande do Sul, Dept Astron, CP 15051, BR-91501970 Porto Alegre, RS - Brazil
Total Affiliations: 4
Document type: Journal article
Source: Monthly Notices of the Royal Astronomical Society; v. 491, n. 3, p. 3251-3265, JAN 2020.
Web of Science Citations: 0

Globular clusters (GCs) are the most ancient stellar systems in the Milky Way. Therefore, they play a key role in the understanding of the early chemical and dynamical evolution of our Galaxy. Around 40 per cent of them are placed within similar to 4 kpc from the Galactic centre. In that region, all Galactic components overlap, making their disentanglement a challenging task. With Gaia Data Release 2, we have accurate absolute proper motions for the entire sample of known GCs that have been associated with the bulge/bar region. Combining them with distances, from RR Lyrae when available, as well as radial velocities from spectroscopy, we can perform an orbital analysis of the sample, employing a steady Galactic potential with a bar. We applied a clustering algorithm to the orbital parameters apogalactic distance and the maximum vertical excursion from the plane, in order to identify the clusters that have high probability to belong to the bulge/bar, thick disc, inner halo, or outer halo component. We found that similar to 30 per cent of the clusters classified as bulge GCs based on their location are just passing by the inner Galaxy, they appear to belong to the inner halo or thick disc component, instead. Most GCs that are confirmed to be bulge GCs are not following the bar structure and are older than the epoch of the bar formation. (AU)

FAPESP's process: 17/15893-1 - Globular cluster orbits of bulge: the formation and evolution of the Milky Way
Grantee:Maria de Los Angeles Perez Villegas
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 18/22044-3 - Bulge globular clusters: relics of the early formation of the galaxy
Grantee:Stefano Oliveira de Souza
Support type: Scholarships in Brazil - Doctorate (Direct)