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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Halo intruders in the Galactic bulge revealed by HST and Gaia: the globular clusters Terzan 10 and Djorgovski 1

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Autor(es):
Ortolani, S. [1] ; Nardiello, D. [1] ; Perez-Villegas, A. [2] ; Bica, E. [3] ; Barbuy, B. [2]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Vicolo Osservatorio 2, I-35122 Padua - Italy
[2] Univ Sao Paulo, IAG, Rua Matao 1226, BR-05508900 Sao Paulo - Brazil
[3] Univ Fed Rio Grande do Sul, Dept Astron, CP 15051, BR-91501970 Porto Alegre, RS - Brazil
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: Astronomy & Astrophysics; v. 622, FEB 1 2019.
Citações Web of Science: 2
Resumo

Context. The low-latitude globular clusters Terzan 10 and Djorgovski 1 are projected in the Galactic bulge, in a Galactic region highly affected by extinction. A discrepancy of a factor of similar to 2 exists in the literature in regards to the distance determination of these clusters. Aims. We revisit the colour-magnitude diagrams (CMDs) of these two globular clusters with the purpose of disentangling their distance determination ambiguity and, for the first time, of determining their orbits to identify whether or not they are part of the bulge/bar region. Methods. We use Hubble Space Telescope CMDs, with the filters F606W from ACS and F160W from WFC3 for Terzan 10, and F606W and F814W from ACS for Djorgosvski 1, and combine them with the proper motions from Gaia Data Release 2. For the orbit integrations, we employed a steady Galactic model with bar. Results. For the first time the blue horizontal branch of these clusters is clearly resolved. We obtain reliable distances of d(circle dot) = 10.3 +/- 1.0 kpc and 9.3 +/- 0.5 kpc for Terzan 10, and Djorgovski 1 respectively, indicating that they are both currently located in the bulge volume. From Gaia DR2 proper motions, together with our new distance determination and recent literature radial velocities, we are able to show that the two sample clusters have typical halo orbits that are passing by the bulge/bar region, but that they are not part of this component. For the first time, halo intruders are identified in the bulge. (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