Identification of a dwarf galaxy stream in Gaia, and its possible association with the VPOS structure

Abstract

Low surface density streams are important tracers to study the formation and evolution of the Milky Way. Using the accurate astrometric measurements from Gaia mission, we discover a low surface density stream in the north hemisphere, with length of $\sim 110$ degree and width of $1.23$ kpc. The vertical velocity dispersion perpendicular to the stream is around $22.4$ km s${}^{-1}$. The spectral data of member candidate stars from LAMOST and DESI shows a large metallicity range from $-1.8$ to $-0.7$. Based on those properties we claim that the stream is originated from a dwarf galaxy. The median metallicity of $[Fe/H]=-1.3$ indicates a massive dwarf galaxy origination with stellar mass around $2.0\times 10^7{M}_{\odot }$, which is comparable with the Fornax dwarf galaxy and smaller than LMC/SMC and Sagittarius. We also find the globular cluster Pyxis is highly associated with the stream in the phase space $E-L_Z$ and metallicity. The massive progenitor also suggests that many dwarf galaxies, including massive ones, have been disrupted during their evolution orbiting the Milky Way and left with very low surface density structures. This is important to understand the {\it missing satellites} problem. The orbit information of the stream shows tight association between its progenitor and the Vast POlar Structure (VPOS), which indicates that the satellites fell into the Milky Way in groups, which brought many globular clusters into the Milky Way.

arXiv commentsubmitted to AA Letter, this is the updated version after second revision

References in corpus (58)

• The Sloan Digital Sky Survey: Technical Summary
• The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
• A 2MASS All-Sky View of the Sagittarius Dwarf Galaxy: I. Morphology of the Sagittarius Core and Tidal Arms
• The Mass-Metallicity Relation at z~2
• The Dark Energy Survey: more than dark energy - an overview
• The Universal Stellar Mass-Stellar Metallicity Relation for Dwarf Galaxies
• AGAMA: Action-based galaxy modelling architecture
• Galaxies in N-body simulations: overcoming the overmerging problem
• The Optical to Mid-Infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS and WISE Surveys
• Origin of the system of globular clusters in the Milky Way
• Tracing Galaxy Formation with Stellar Halos II: Relating Substructure in Phase- and Abundance-Space to Accretion Histories
• Streams, substructures and the early history of the Milky Way
• Evidence from the H3 Survey that the Stellar Halo is Entirely Comprised of Substructure
• The Luminosity Function of the Milky Way Satellites
• The VPOS: a vast polar structure of satellite galaxies, globular clusters and streams around the Milky Way
• Detection of a 63 Degree Cold Stellar Stream in the Sloan Digital Sky Survey
• Modeling the Metallicity Distribution of Globular Clusters
• The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrographs
• An Orphan in the "Field of Streams"
• Stellar Streams Discovered in the Dark Energy Survey
• Galactic Halo substructure in the Sloan Digital Sky Survey: the ancient tidal stream from the Sagittarius dwarf galaxy
• Four New Stellar Debris Streams in the Galactic Halo
• Detection of a 60 Degree-Long Dwarf Galaxy Debris Stream
• The nucleus of the Sagittarius dSph galaxy and M54: a window on the process of galaxy nucleation
• One large blob and many streams frosting the nearby stellar halo in Gaia DR2
• The Chemical Evolution of Star-Forming Galaxies Over the Last 11 Billion Years
• Milky Way Satellite Census. I. The Observational Selection Function for Milky Way Satellites in DES Y3 and Pan-STARRS DR1
• Detection of a 45 Degree Tidal Stream Associated with the Globular Cluster NGC 5466
• Mapping the Stellar Halo with the H3 Spectroscopic Survey
• Planck intermediate results. XXIX. All-sky dust modelling with Planck, IRAS, and WISE observations
• Discovery of a New, Polar-Orbiting Debris Stream in the Milky Way Stellar Halo
• Low Masses and High Redshifts: The Evolution of the Mass-Metallicity Relation
• The Southern Stellar Stream Spectroscopic Survey ($S^5$): Overview, Target Selection, Data Reduction, Validation, and Early Science
• STREAMFINDER I: A New Algorithm for detecting Stellar Streams
• The origin of the Milky Way globular clusters
• $S^5$: Probing the Milky Way and Magellanic Clouds potentials with the 6-D map of the Orphan-Chenab stream
• The Absolute Proper Motion of Palomar 12: A Case for Tidal Capture from the Sagittarius Dwarf Spheroidal Galaxy
• A Low-Mass Stellar-Debris Stream Associated with a Globular Cluster Pair in the Halo
• Fourteen candidate RR Lyrae star streams in the inner Galaxy
• The Gaia DR3 view of dynamical substructure in the stellar halo near the Sun
• Evidence of a dwarf galaxy stream populating the inner Milky Way Halo
• Remnants of Sagittarius Dwarf Spheroidal Galaxy around the young globular cluster Palomar 12
• A search for stellar tidal debris of defunct dwarf galaxies around globular clusters in the inner Galactic halo
• The nucleation fraction of Local Volume galaxies
• The Complexity of the Cetus Stream Unveiled from the Fusion of STREAMFINDER and StarGO
• The Milky Way's stellar streams and globular clusters do not align in a Vast Polar Structure
• On the genealogy of the Orphan Stream
• Phase-space correlation in stellar streams of the Milky Way halo: The clash of Kshir and GD-1
• Is NGC 5824 the Core of the Progenitor of the Cetus Stream?
• Two New Halo Debris Streams in the Sloan Digital Sky Survey
• Velocity Dispersion of the GD-1 Stellar Stream
• Identifying Galactic Halo Substructure in 6D Phase-space Using $\sim$13,000 LAMOST K Giants
• Detection of a Nearby Halo Debris Stream in the WISE and 2MASS Surveys
• The Cetus-Palca stream: A disrupted small dwarf galaxy. A prequel to the science possible with WEAVE with precise spectro-photometric distances
• The Proper Motion of Pyxis: the first use of Adaptive Optics in tandem with HST on a faint halo object
• The Extended Tidal Tails of NGC 7089 (M2)
• Searching Extra-tidal Features around the Globular Cluster Whiting 1
• A New Tidal Stream Discovered in Gaia DR3

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