The Sausage Globular Clusters

By G. Myeong, N. Evans II, V. Belokurov, J. Sanders, Sergey E. Koposov. Astrophysical Journal, 2018

167 citations recorded by the source corpus.

The Gaia Sausage is an elongated structure in velocity space discovered by Belokurov et al. using the kinematics of metal-rich halo stars. They showed that it could be created by a massive dwarf galaxy (∼5 × 1010 ) on a strongly radial orbit that merged with the Milky Way at a redshift z ≲ 3. This merger would also have brought in globular clusters (GCs). We seek evidence for the associated Sausage Globular Clusters (GCs) by analyzing the structure of 91 Milky Way GCs in action space using the Gaia Data Release 2 catalog, complemented with Hubble Space Telescope proper motions. There is a characteristic energy that separates the in situ objects, such as the bulge/disk clusters, from the accreted objects, such as the young halo clusters. There are 15 old halo GCs that have E > . 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 (β ∼ 0.95) and move on orbits that are all highly eccentric (e ≳ 0.80). They also form a track in the age–metallicity plane compatible with a dwarf galaxy origin. These properties are consistent with GCs associated with the merger event that gave rise to the Gaia Sausage.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/085cb0a427ca907429b1a3672b62888ea0c66361

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Citations in the corpus

Evidence for an Intermediate-mass Milky Way from Gaia DR2 Halo Globular Cluster Motions (2018, background): “However, there have been recent claims that up to two thirds of the local stellar halo may have been deposited by the single encounter of a massive dwarf galaxy (e.g., Deason et al. 2013; Belokurov et al. 2018; Myeong et al. 2018).”
Mean proper motions, space orbits, and velocity dispersion profiles of Galactic globular clusters derived fromGaiaDR2 data (2018, background): “This information will be useful to understand the formation history of the Milky Way halo (accreted vs. in-situ) (e.g Myeong et al. 2018), the total mass of the Milky Way and the shape of its dark matter halo using globular cluster orbits (e.g Posti & Helmi 2018), the formation of massive star…”
Evidence for two early accretion events that built the Milky Way stellar halo (2019, methodology): “Note that the retrograde component of halo stars has also been scoured to provide evidence of multiple minor mergers and accretion events (e.g., Helmi et al. 2017; Myeong et al. 2018c,b).”
The biggest splash (2019, methodology): “Myeong et al. (2018c) complemented the sample provided by Kruijssen et al. (2019) with the GC orbital properties from Gaia Collaboration et al. (2018c) to discover a large group of clusters likely originating from the GS dwarf galaxy (see also Piatti & Carballo-Bello 2019), thus confirming the high…”
The origin of accreted stellar halo populations in the Milky Way using APOGEE,Gaia, and the EAGLE simulations (2018, methodology): “…of the Milky Way today, suggesting that this population is likely the progeny of a single, massive accretion event which occurred early in the history of the Milky Way Galaxy, as suggested by other groups (e.g. Myeong et al. 2018b; Deason et al. 2018; Helmi et al. 2018; Belokurov et al. 2018).”
Evidence from the H3 Survey That the Stellar Halo Is Entirely Comprised of Substructure (2020, methodology): “Debris of the Sequoia dwarf galaxy (Myeong et al. 2018c, 2019; Matsuno et al. 2019) dominates the local retrograde halo at higher energies while Thamnos (Koppelman et al. 2019a) resides at lower energy.”
Proper motions and dynamics of the Milky Way globular cluster system fromGaiaDR2 (2018, methodology): “This population was identified by Myeong et al. (2018) and associated with a similar radially-biased population in the stellar halo.”
The formation and assembly history of the Milky Way revealed by its globular cluster population (2018, methodology): “The Myeong et al. (2018) GC sample closely matches the ‘Canis Major’ candidate GCs listed in Section 5.1, implying that these were likely not brought in by Kraken.”