VVV CL001: Likely the Most Metal-poor Surviving Globular Cluster in the Inner Galaxy

Autor(es):Mostrar menos -

Fernandez-Trincado, Jose G. ^{[1, 2, 3]} ; Minniti, Dante ^{[4, 5]} ; Souza, Stefano O. ^[6] ; Beers, Timothy C. ^{[7, 8]} ; Geisler, Doug ^{[9, 10, 11]} ; Bidin, Christian Moni ^[12] ; Villanova, Sandro ^[9] ; Majewski, Steven R. ^[13] ; Barbuy, Beatriz ^[6] ; Perez-Villegas, Angeles ^[14] ; Henao, Lady ^[9] ; Romero-Colmenares, Maria ^[15] ; Roman-Lopes, Alexandre ^[10] ; Lane, Richard R. ^[1]

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

^[1] Univ Atacama, Inst Astron & Ciencias Planetarias, Copayapu 485, Copiapo - Chile

^[2] Univ Bourgogne Franche Comte, OSU THETA Franche Comte, Observ Besancon, Inst Utinam, CNRS, UMR 6213, BP 1615, F-25010 Besancon - France

^[3] Univ Bernardo O Higgins, Ctr Invest Astron, Ave Viel 1497, Santiago - Chile

^[4] Vatican Observ, V-00120 Vatican City - Vatican

^[5] Univ Andres Bello, Fac Ciencias Exactas, Dept Cs Fis, Av Fernandez Concha 700, Santiago - Chile

^[6] Univ Sao Paulo, IAG, Rua Matao 1226, BR-05508900 Sao Paulo - Brazil

^[7] Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 - USA

^[8] Univ Notre Dame, JINA Ctr Evolut Elements, Notre Dame, IN 46556 - USA

^[9] Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion - Chile

^[10] Univ La Serena, Dept Astron, Av Juan Cisternas 1200 North, La Serena - Chile

^[11] Univ La Serena, Inst Invest Multidisciplinario Ciencia & Tecnol, Benavente 980, La Serena - Chile

^[12] Univ Catolica Norte, Inst Astron, Av Angamos 0610, Antofagasta - Chile

^[13] Univ Virginia, Dept Astron, Charlottesville, VA 22904 - USA

^[14] Univ Nacl Autonoma Mexico, Inst Astron, Apdo Postal 106, Ensenada 22800, BC - Mexico

^[15] Univ Antofagasta, Ctr Astron CITEVA, Av Angamos 601, Antofagasta - Chile

• Tipo de documento: Artigo Científico
• Fonte: Astrophysical Journal Letters; v. 908, n. 2 FEB 2021.
• Citações Web of Science: 0

Resumo

We present the first high-resolution abundance analysis of the globular cluster VVV CL001, which resides in a region dominated by high interstellar reddening toward the Galactic bulge. Using H-band spectra acquired by the Apache Point Observatory Galactic Evolution Experiment, we identified two potential members of the cluster, and estimated from their Fe I lines that the cluster has an average metallicity of {[}Fe/H] = -2.45 with an uncertainty due to systematics of 0.24 dex. We find that the light-(N), alpha-(O, Mg, Si), and Odd-Z (Al) elemental abundances of the stars in VVV CL001 follo w the same trend as other Galactic metal-poor globular clusters. This makes VVV CL001 possibly the most metalpoor globular cluster identified so far within the Sun's galactocentric distance and likely one of the most metaldeficient clusters in the Galaxy after ESO280-SC06. Applying statistical isochrone fitting, we derive self-consistent age, distance, and reddening values, yielding an estimated age of 11.9(-4.05)(+3.12) Gyr at a distance of 8.22(-1.93)(+1.84) kpc, revealing that VVV CL001 is also an old GC in the inner Galaxy. The Galactic orbit of VVV CL001 indicates that this cluster lies on a halo-like orbit that appears to be highly eccentric. Both chemistry and dynamics support the hypothesis that VVV CL001 could be an ancient fossil relic left behind by a massive merger event during the early evolution of the Galaxy, likely associated with either the Sequoia or the Gaia-Enceladus-Sausage structures. (AU)

• Processo FAPESP: 18/22044-3 - Aglomerados globulares do bojo: relíquias da formação e evolução da galáxia
• Beneficiário: Stefano Oliveira de Souza
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto