On Rings and Streams in the Galactic Anti-Center

Abstract

We confirm that there are at least three separate low-latitude over-densities of blue F turnoff stars near the Milky Way anti-center: the Monoceros Ring, the Anti-Center Stream (ACS), and the Eastern Banded Structure (EBS). There might also be a small number of normal thick disk stars at the same location. The ACS is a tilted component that extends to higher Galactic latitude at lower Galactic longitude, 10 kpc from the Sun towards the anti-center. It has a sharp cutoff on the high latitude side. Distance, velocity, and proper motion measurements are consistent with previous orbit fits. The mean metallicity is [Fe/H]$=-0.96\pm 0.03$, which is lower than the thick disk and Monoceros Ring. The Monoceros Ring is a higher density substructure that is present at $15\arcdeg<b<22\arcdeg$ at all longitudes probed in this survey. The structure likely continues towards lower latitudes. The distances are consistent with a constant distance from the Galactic Center of 17.6 kpc. The mean line-of-sight velocity of the structure is consistent with a thick disk rotation. However, the velocity dispersion of these stars is $\sim 15$ km s${}^{-1}$, and the metallicity is [Fe/H]$=-0.80\pm 0.01$. Both of these quantities are lower than the canonical thick disk. We suggest that this ring structure is likely different from the thick disk, though its association with the disk cannot be definitively ruled out. The Eastern Banded Structure (EBS) is detected primarily photometrically, near $(l,b)=(225\arcdeg,30\arcdeg)$, at a distance of 10.9 kpc from the Sun.

56 pages, 4 tables, 23 figures, submitted to APJ

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Cited by in corpus (32)

• Rings and Radial Waves in the Disk of the Milky Way
• LAMOST Spectroscopic Survey of the Galactic Anti-centre (LSS-GAC): target selection and the first release of value-added catalogues
• Stellar Streams and Clouds in the Galactic Halo
• Galactic Archaeology. The dwarfs that survived and perished
• Gaia Early Data Release 3: The Galactic anticentre
• Flare in the Galactic stellar outer disc detected in SDSS-SEGUE data
• Mapping the Milky Way with LAMOST III: Complicated spatial structure in the outer disc
• The Complex Structure of Stars in the Outer Galactic Disk as revealed by Pan-STARRS1
• The Pristine survey VIII: The metallicity distribution function of the Milky Way halo down to the extremely metal-poor regime
• Chemo-dynamical properties of the Anticenter Stream: a surviving disc fossil from a past satellite interaction
• Exploring Halo Substructure with Giant Stars: The Nature of the Triangulum-Andromeda Stellar Features
• Mapping the Monoceros Ring in 3D with Pan-STARRS1
• The fall of the Northern Unicorn: Tangential motions in the Galactic Anti-centre with SDSS and Gaia
• Exploring the pertubed Milky Way disk and the substructures of the outer disk
• A skewer survey of the Galactic halo from deep CFHT and INT images
• Tracing the tidal streams of the Sagittarius dSph, and halo Milky Way features, with carbon-rich long-period variables
• Spontaneous generation of bending waves in isolated Milky Way-like discs
• Kinematic Discovery of a Stellar Stream located in Pisces
• Abundances and kinematics for ten anticentre open clusters
• VVVX-Gaia Discovery of a Low Luminosity Globular Cluster in the Milky Way Disk
• Identifying Galactic Halo Substructure in 6D Phase-space Using $\sim$13,000 LAMOST K Giants
• Update on the Cetus Polar Stream and its Progenitor
• A Spatial Characterization of the Sagittarius Dwarf Galaxy Tidal Tails
• Exploring the Galactic Anticenter substructure with LAMOST & Gaia DR2
• Tails from the Orphanage
• Differential rotation of the halo traced by the K-giant stars
• Using measurements of the cosmic bulk flow to constrain $f(R)$ Gravity
• A Megacam Survey of Outer Halo Satellites. IV. Two foreground populations possibly associated with the Monoceros substructure in the direction of NGC2419 and Koposov2
• Evidence That Hydra I is a Tidally Disrupting Milky Way Dwarf Galaxy
• Comments on the "Monoceros" affair
• Unveiling Galactic substructures with M Giant stars: A kinematic and chemical study based on LAMOST DR9, Gaia DR3 and APOGEE DR17
• New tidal debris nearby the Sagittarius leading tail from the LAMOST DR2 M giant stars