The Sausage Globular Clusters
Autor: | G. C. Myeong, Nick Evans, Sergey E. Koposov, Vasily Belokurov, Jason L. Sanders |
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Přispěvatelé: | Myeong, Gyuchul [0000-0002-5629-8876], Evans, Wyn [0000-0002-5981-7360], Belokurov, Vasily [0000-0002-0038-9584], Sanders, Jason [0000-0003-4593-6788], Koposov, Sergey [0000-0003-2644-135X], Apollo - University of Cambridge Repository |
Rok vydání: | 2018 |
Předmět: |
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
astro-ph.GA Milky Way FOS: Physical sciences Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics 01 natural sciences Bulge 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics galaxies: kinematics and dynamics Astrophysics::Galaxy Astrophysics Dwarf galaxy Physics 010308 nuclear & particles physics Astronomy and Astrophysics Astrophysics - Astrophysics of Galaxies Redshift Orbit Stars Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) Globular cluster astro-ph.CO galaxies: structure Astrophysics::Earth and Planetary Astrophysics Halo Astrophysics - Cosmology and Nongalactic Astrophysics |
Zdroj: | Myeong, G C, Evans, N W, Belokurov, V, Sanders, J L & Koposov, S E 2018, ' The Sausage Globular Clusters ', Astrophysical Journal Letters . https://doi.org/10.3847/2041-8213/aad7f7 |
ISSN: | 2041-8213 |
Popis: | The Gaia Sausage is an elongated structure in velocity space discovered by Belokurov et al. (2018) using the kinematics of metal-rich halo stars. It was created by a massive dwarf galaxy ($\sim 5 \times 10^{10} M_\odot$) on a strongly radial orbit that merged with the Milky Way at a redshift $z\lesssim 3$. We search forthe associated Sausage Globular Clusters by analysing the structure of 91 Milky Way globular clusters (GCs) in action space using the Gaia Data Release 2 catalogue, complemented with Hubble Space Telescope proper motions. There is a characteristic energy $E_{\rm crit}$ which separates the in situ objects, such as the bulge/disc clusters, from the accreted objects, such as the young halo clusters. There are 15 old halo GCs that have $E > E_{\rm crit}$. Eight of the high energy, old halo GCs are strongly clumped in azimuthal and vertical action, yet strung out like beads on a chain at extreme radial action. They are very radially anisotropic ($\beta \sim 0.95$) and move on orbits that are all highly eccentric ($e \gtrsim 0.80$). They also form a track in the age-metallicity plane distinct from the bulk of the Milky Way GCs and compatible with a dwarf spheroidal origin. These properties are consistent with GCs associated with the merger event that gave rise to the Gaia Sausage. Comment: ApJL, revised version |
Databáze: | OpenAIRE |
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