Статья

Stellar Populations in the Central 0.5 pc of Our Galaxy. III. The Dynamical Substructures

Siyao JiaAstronomy Department, University of California, Berkeley, CA 94720, USA; [email protected], [email protected]Ningyuan XuAstronomy Department, University of California, Berkeley, CA 94720, USA; [email protected], [email protected]Jessica R. LuAstronomy Department, University of California, Berkeley, CA 94720, USA; [email protected], [email protected]Devin S. ChuUCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USAKelly Kosmo O’NeilUCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USAW. B. DrechslerAstronomy Department, University of California, Berkeley, CA 94720, USA; [email protected], [email protected]Matthew HosekUCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USAShoko SakaiUCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USATuan DoUCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USAAnna CiurloUCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USAAbhimat K. GautamUCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USAA. M. GhezUCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USAE. E. BecklinUCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USAM. MorrisUCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USARory O. BentleyUCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547, USA

2023en

ABI

Аннотация

Abstract We measure the 3D kinematic structures of the young stars within the central 0.5 pc of our Galactic Center using the 10 m telescopes of the W. M. Keck Observatory over a time span of 25 yr. Using high-precision measurements of positions on the sky and proper motions and radial velocities from new observations and the literature, we constrain the orbital parameters for each young star. Our results show two statistically significant substructures: a clockwise stellar disk with 18 candidate stars, as has been proposed before, but with an improved disk membership; and a second, almost edge-on plane of 10 candidate stars oriented east–west on the sky that includes at least one IRS 13 star. We estimate the eccentricity distribution of each substructure and find that the clockwise disk has 〈 e 〉 = 0.39 and the edge-on plane has 〈 e 〉 = 0.68. We also perform simulations of each disk/plane with incompleteness and spatially variable extinction to search for asymmetry. Our results show that the clockwise stellar disk is consistent with a uniform azimuthal distribution within the disk. The edge-on plane has an asymmetry that cannot be explained by variable extinction or incompleteness in the field. The orientation, asymmetric stellar distribution, and high eccentricity of the edge-on plane members suggest that this structure may be a stream associated with the IRS 13 group. The complex dynamical structure of the young nuclear cluster indicates that the star formation process involved complex gas structures and dynamics and is inconsistent with a single massive gaseous disk.

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Идентификаторы

DOI: 10.3847/1538-4357/acb939

Цитирования и источники

Цитирований: 3Использованных источников: 0

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