The GALAH survey: stellar streams and how stellar velocity distributions vary with Galactic longitude, hemisphere, and metallicity
Article
Article Title | The GALAH survey: stellar streams and how stellar velocity distributions vary with Galactic longitude, hemisphere, and metallicity |
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ERA Journal ID | 1074 |
Article Category | Article |
Authors | Quillen, Alice C. (Author), de Silva, Gayandhi (Author), Sharma, Sanjib (Author), Hayden, Michael (Author), Freeman, Ken (Author), Bland-Hawthorn, Joss (Author), Zerjal, Marusa (Author), Asplund, Martin (Author), Buder, Sven (Author), D'Orazi, Valentina (Author), Duong, Ly (Author), Kos, Janez (Author), Lin, Jane (Author), Lind, Karin (Author), Martell, Sarah (Author), Schlesinger, Katharine (Author), Simpson, Jeffrey D. (Author), Zucker, Daniel B. (Author), Zwitter, Tomaz (Author), Anguiano, Borja (Author), Carollo, Daniela (Author), Casagrande, Luca (Author), Cotar, Klemen (Author), Cottrell, Peter L. (Author), Ireland, Michael (Author), Kafle, Prajwal R. (Author), Horner, Jonathan (Author), Lewis, Geraint F. (Author), Nataf, David M. (Author), Ting, Yuan-Sen (Author), Watson, Fred (Author), Wittenmyer, Rob (Author) and Wyse, Rosemary (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 478 (12), pp. 228-254 |
Number of Pages | 27 |
Year | 2018 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1093/mnras/sty865 |
Web Address (URL) | https://academic.oup.com/mnras/article/478/1/228/4962405 |
Abstract | Using GALAH (GALactic Archaeology with HERMES) survey data of nearby stars, we look at how structure in the planar (u, v) velocity distribution depends on metallicity and on viewing direction within the Galaxy. In nearby stars with distance d ≲ 1 kpc, the Hercules stream is most strongly seen in higher metallicity stars [Fe/H] > 0.2. The Hercules stream peak v value depends on viewed galactic longitude, which we interpret as due to the gap between the stellar stream and more circular orbits being associated with a specific angular momentum value of about 1640 km s<SUP>-1</SUP> kpc. The association of the gap with a particular angular momentum value supports a bar resonant model for the Hercules stream. Moving groups previously identified in Hipparcos(HIgh Precision Parallax COllecting Satellite) observations are easiest to see in stars nearer than 250 pc, and their visibility and peak velocities in the velocity distributions depends on both viewing direction (galactic longitude and hemisphere) and metallicity. We infer that there is fine structure in local velocity distributions that varies over distances of a few hundred pc in the Galaxy. |
Keywords | galaxies; evolution; kinematics and dynamics; astrophysics; astrophysics of galaxies |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2018 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Institution of Origin | University of Southern Queensland |
Byline Affiliations | University of Rochester, United States |
Australian Astronomical Observatory, Australia | |
University of Sydney | |
Australian National University | |
Max Planck Society, Germany | |
National Institute for Astrophysics, Italy | |
University of New South Wales | |
Macquarie University | |
University of Ljubljana, Slovenia | |
ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions, Australia | |
University of Canterbury, New Zealand | |
University of Western Australia | |
Division of Research and Innovation | |
Johns Hopkins University, United States | |
Institute for Advanced Study, United States | |
Computational Engineering and Science Research Centre |
https://research.usq.edu.au/item/q518y/the-galah-survey-stellar-streams-and-how-stellar-velocity-distributions-vary-with-galactic-longitude-hemisphere-and-metallicity
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