Identification of Sagittarius stream members in Angular Momentum space with Gaussian mixture techniques

Abstract

This paper uses Gaussian mixture techniques to dissect the Milky Way (MW) stellar halo in angular momentum space. Application to a catalogue of 5389 stars near the plane of the Sagittarius (Sgr) stream with full 6D phase-space coordinates supplied by Gaia EDR3 and SEGUE returns four independent dynamical components. The broadest and most populated corresponds to the `smooth' MW halo. The narrowest and faintest contains 40 stars of the Orphan stream. We find a component with little or no angular momentum likely associated with the GSE substructure. We also identify 925 stars and 7 Globular Clusters with probabilities $>90\%$ to be members of the Sgr stream. Comparison against $N$-body models shows that some of these members trace the continuation of the leading/trailing tails in the Southern/Northern hemispheres. The new detections span $\sim 800^{\circ }$ on the sky, thus wrapping the Galaxy {\it twice}.

Submitted to MNRAS Letters. Comments welcome

References in corpus (11)

• The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars
• Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST and literature data
• The last breath of the Sagittarius dSph
• Detection of the Milky Way reflex motion due to the Large Magellanic Cloud infall
• Reflex motion in the Milky Way stellar halo resulting from the Large Magellanic Cloud infall
• Predicted Extension of the Sagittarius Stream to the Milky Way Virial Radius
• Tracing Kinematic and Chemical Properties of Sagittarius Stream by K-Giants, M-Giants, and BHB stars
• Revealing the Structure and Internal Rotation of the Sagittarius Dwarf Spheroidal Galaxy with Gaia and Machine Learning
• Detecting the Sagittarius stream with LAMOST DR4 M giants \& Gaia DR2
• The course of the Orphan Stream in the Northern Galactic Hemisphere traced with Gaia DR2
• Globular Clusters Lost by the Sagittarius Dwarf Spheroidal Galaxy

Cited by in corpus (6)

• The Unmixed Debris of Gaia-Sausage/Enceladus in the Form of a Pair of Halo Stellar Overdensities
• The SDSS-Gaia View of the Color-Magnitude Relation for Blue Horizontal-branch Stars
• A Pristine-UNIONS view on the Galaxy: Kinematics of the distant spur feature of the Sagittarius stream traced by Blue Horizontal Branch stars
• Mapping the Distant and Metal-Poor Milky Way with SDSS-V
• Globular clusters as indicators of Galactic evolution
• Kinematics of the Sagittarius Dwarf Spheroidal core: A 5D Analysis for a 6D Methodology with Gaia DR3