The metal-rich halo tail extended in vertical bar z vertical bar: a characterization with Gaia DR2 and APOGEE

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Fernandez-Alvar, Emma ^{[1, 2]} ; Fernandez-Trincado, Jose G. ^{[3, 4]} ; Moreno, Edmundo ^[1] ; Schuster, William J. ^[5] ; Carigi, Leticia ^[1] ; Recio-Blanco, Alejandra ; Beers, Timothy C. ^{[6, 7]} ; Chiappini, Cristina ^{[8, 9]} ; Anders, Friedrich ^{[8, 9]} ; Santiago, Basilio X. ^{[10, 9]} ; Queiroz, Anna B. A. ^{[10, 9]} ; Perez-Villegas, Angeles ^[11] ; Zamora, Olga ^[12] ; Garcia-Hernandez, D. A. ^[12] ; Ortigoza-Urdaneta, Mario ^[3]

Afiliação do(s) autor(es):Mostrar menos -

^[1] Univ Nacl Autonoma Mexico, Inst Astron, AP 70-264, Ciudad De Mexico 04510 - Mexico

^[2] Univ Cote Azur, Observ Cote Azur, Lab Lagrange, CNRS, F-06300 Nice - France

^[3] Univ Atacama, Inst Astron & Ciencias Planetarias, Copayapu 485, Copiapo - Chile

^[4] Univ Bourgogne Franche Comte, CNRS UMR6213, Inst Utinam, OSU THETA, Observ Besancon, BP 1615, F-25010 Besancon - France

^[5] Univ Nacl Autonoma Mexico, Inst Astron, AP 106, Ensenada 22800, Baja California - Mexico

^[6] Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 - USA

^[7] Univ Notre Dame, JINA CEE, Notre Dame, IN 46556 - USA

^[8] Leibniz Inst Astrophys Potsdam AIP, Sternwarte 16, D-14482 Potsdam - Germany

^[9] Lab Int E Astron Linea, Rua Gal Jose Cristino 77, BR-20921400 Rio De Janeiro - Brazil

^[10] Univ Fed Rio Grande do Sul, Inst Fis, Caixa Postal 15051, BR-91501970 Porto Alegre, RS - Brazil

^[11] Univ Sao Paulo, IAG, Rua Matao 1226, Cidade Univ, BR-05508900 Sao Paulo - Brazil

^[12] Inst Astrofis Canarias, E-38205 San Cristobal la Laguna, Tenerife - Spain

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 487, n. 1, p. 1462-1479, JUL 2019.
• Citações Web of Science: 3

Resumo

We report an analysis of the metal-rich tail ({[}Fe/H] > -0.75) of stars located at distances from the Galactic plane up to vertical bar z vertical bar similar to 10 kpc, observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE). We examine the chemistry, kinematics, and dynamics of this metal-rich sample using chemical abundances and radial velocities provided by the 14th APOGEE data release (DR14) and proper motions from the second Gaia data release (DR2). The analysis reveals three chemically different stellar populations in the {[}Mg/Fe] versus {[}Fe/H] space - a high-{[}Mg/Fe] and low-{[}Mg/Fe] populations, and a third group with intermediate {[}Mg/Fe] similar to +0.1 - as well as for other chemical elements. We find that they are also kinematically and dynamically distinct. The high-{[}Mg/Fe] population exhibits a prograde rotation which decreases down to 0 as vertical bar z(max)vertical bar increases, as well as eccentric orbits that are more bound and closer to the plane. The low-{[}Mg/Fe] stars are likely Sagittarius members, moving in less-bound orbits reaching larger distances from the centre and the Galactic plane. The intermediate-{[}Mg/Fe] stars resembles the two stellar overdensities lying about vertical bar z vertical bar similar to 5 kpc recently reported in the literature, for which a disc origin has been claimed. We report the identification of new members of these two disc-heated overdensities. (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