Globular clusters in the inner Galaxy classified from dynamical orbital criteria

Autor(es)

Perez-Villegas, Angeles ^[1] ; Barbuy, Beatriz ^[1] ; Kerber, Leandro O. ^[2] ; Ortolani, Sergio ^[3] ; Souza, Stefano O. ^[1] ; Bica, Eduardo ^[4]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 491, n. 3, p. 3251-3265, JAN 2020.
• Citações Web of Science: 0

Resumo

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)

• Processo FAPESP: 17/15893-1 - Órbitas de aglomerados globulares do bojo: formação e evolução da Via Láctea
• Beneficiário: Maria de Los Angeles Perez Villegas
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 18/22044-3 - Aglomerados globulares do bojo: relíquias da formação e evolução da galáxia
• Beneficiário: Stefano Oliveira de Souza
• Linha de fomento: Bolsas no Brasil - Doutorado Direto