New detections of embedded clusters in the Galactic halo

Abstract

Until recently it was thought that high Galactic latitude clouds were a non-star-forming ensemble. However, in a previous study we reported the discovery of two embedded clusters (ECs) far away from the Galactic plane ($\sim 5$ kpc). In our recent star cluster catalogue we provided additional high and intermediate latitude cluster candidates. This work aims to clarify if our previous detection of star clusters far away from the disc represents just an episodic event or if the star cluster formation is currently a systematic phenomenon in the Galactic halo. We analyse the nature of four clusters found in our recent catalogue and report the discovery of three new ECs with unusually high latitude and distance from the Galactic disc midplane. All of these clusters are younger than 5 Myr. The high-latitude ECs C 932, C 934, and C 939 appear to be related to a cloud complex about 5 kpc below the Galactic disc, under the Local arm. The other clusters are above the disc, C 1074 and C 1100 with a vertical distance of $\sim 3$ kpc, C 1099 with $\sim 2$ kpc, and C 1101 with $\sim 1.8$ kpc. According to the derived parameters there occur ECs located below and above the disc, which is an evidence of widespread star cluster formation throughout the Galactic halo. Thus, this study represents a paradigm shift, in the sense that a sterile halo becomes now a host of ongoing star formation. The origin and fate of these ECs remain open. There are two possibilities for their origin, Galactic fountain or infall. The discovery of ECs far from the disc suggests that the Galactic halo is more actively forming stars than previously thought and since most ECs do not survive the \textit{infant mortality} it may be raining stars from the halo into the disc, and/or the halo harbours generations of stars formed in clusters like those hereby detected.

arXiv comment9 pages, 11 figures

References in corpus (64)

• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Embedded Clusters in Molecular Clouds
• How Do Galaxies Get Their Gas?
• GAIA: Composition, Formation and Evolution of the Galaxy
• Abundance Gradients and the Formation of the Milky Way
• Cold gas accretion in galaxies
• Eight New Milky Way Companions Discovered in First-Year Dark Energy Survey Data
• Beasts of the Southern Wild: Discovery of nine Ultra Faint satellites in the vicinity of the Magellanic Clouds
• Eight Ultra-faint Galaxy Candidates Discovered in Year Two of the Dark Energy Survey
• Gaseous Galaxy Halos
• Multi-Phase Galaxy Formation: High Velocity Clouds and the Missing Baryon Problem
• High Velocity Clouds: Building Blocks of the Local Group
• The cold gaseous halo of NGC 891
• Gas accretion as the origin of chemical abundance gradients in distant galaxies
• On the Continuing Formation of the Andromeda Galaxy: Detection of HI Clouds in the M31 Halo
• The Age of the Solar Neighbourhood
• The Fate of High-Velocity Clouds: Warm or Cold Cosmic Rain?
• Open clusters in dense fields: the importance of field-star decontamination for NGC5715, Lynga4, Lynga9, Trumpler23, Trumpler26 and Czernik37
• Cooling flows within galactic haloes: the kinematics and properties of infalling multi-phase gas
• A new, kinematically anomalous HI component in the spiral galaxy NGC 2403
• Gas Condensation in the Galactic Halo
• The Magellanic Stream System: I. Ram-pressure tails and the relics of the collision between the Magellanic Clouds
• Where are the high velocity clouds?
• GHIGLS: HI mapping at intermediate Galactic latitude using the Green Bank Telescope
• High Velocity Rain: The Terminal Velocity of Model of Galactic Infall
• Integral Field Unit Observations of NGC 4302: Kinematics of the Diffuse Ionized Gas Halo
• The nature of the young and low-mass open clusters Pismis5, vdB80, NGC1931 and BDSB96
• HI study of the warped spiral galaxy NGC5055: a disk/dark matter halo offset?
• Hydrodynamical simulations of Galactic fountains II: evolution of multiple fountains
• Hydrodynamical simulations of Galactic fountains I: evolution of single fountains
• Estimating gas accretion in disc galaxies using the Kennicutt-Schmidt law
• Digging deeper into the Southern skies: a compact Milky-Way companion discovered in first-year Dark Energy Survey data
• Effects of Galactic fountains and delayed mixing in the chemical evolution of the Milky Way
• The Ophiuchus Superbubble: A Gigantic Eruption from the Inner Disk of the Milky Way
• The Accretion of Gas onto Galaxies as Traced by their Satellites
• The fate of the pre-main sequence-rich clusters Collinder197 and vdB92: dissolution?
• The Origin and Distribution of Cold Gas in the Halo of a Milky Way-Mass Galaxy
• Probing FSR star cluster candidates in bulge/disk directions with 2MASS colour-magnitude diagrams
• Tracing the Galactic spiral structure with embedded clusters
• The Smith Cloud: high-velocity accretion and dark-matter confinement
• Characterizing star cluster formation with WISE: 652 newly found star clusters and candidates
• Tracing the tidal streams of the Sagittarius dSph, and halo Milky Way features, with carbon-rich long-period variables
• The Magellanic Stream: break up and accretion onto the hot Galactic corona
• 3D Dust Mapping Reveals that Orion Forms Part of a Large Ring of Dust
• Triggered Star Formation on the Border of the Orion-Eridanus Superbubble
• The Gaseous Trail of the Sagittarius Dwarf Galaxy
• Discovering Protostars and their Host Clusters via WISE
• Investigating the borderline between a young star cluster and a small stellar association: a test case with Bochum1
• A possible sequential star formation in the giant molecular cloud G174+2.5
• Astrophysical parameters of 14 open clusters projected close to the Galactic plane
• A Low Metallicity Molecular Cloud In The Lower Galactic Halo
• Sensitive 21cm Observations of Neutral Hydrogen in the Local Group near M31
• Towards a census of the Galactic anticentre star clusters: colour-magnitude diagram and structural analyses of a sample of 50 objects
• Star clusters or asterisms? 2MASS CMD and structural analyses of 15 challenging targets
• Structural parameters of star clusters: relations among light, mass and star-count radial profiles and the dependence on photometric depth
• New Galactic embedded clusters and candidates from a WISE Survey
• Towards a census of the Galactic anticentre star clusters - III: tracing the spiral structure in the Outer Disk
• Towards a census of the Galactic anticentre star clusters II: exploring lower overdensities
• Exploring FSR open cluster candidates within $|\Delta \ell |=20^{\circ }$ of the Galactic anticentre
• Detection of satellite remnants in the Galactic Halo with Gaia III. Detection limits for Ultra Faint Dwarf Galaxies
• How can star formation be sustained?
• Discovery of two embedded clusters with WISE in the high Galactic latitude cloud HRK 81.4-77.8
• Do High-Velocity Clouds trace the Dark Matter subhalo population?

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• A Multi-Band Catalog of 10978 Star Clusters, Associations and Candidates in the Milky Way
• The GALAH Survey and Gaia DR2: (Non)existence of five sparse high-latitude open clusters
• Milky Way Tomography with K and M Dwarf Stars: the Vertical Structure of the Galactic Disk
• Three candidate globular clusters discovered in the Galactic bulge
• Discovery of a disrupting open cluster far into the Milky Way halo: a recent star formation event in the leading arm of the Magellanic stream?
• New Galactic Star Clusters Discovered in the Disk Area of the VVVX Survey
• The VVV Open Cluster Project. Near-infrared sequences of NGC6067, NGC6259, NGC4815, Pismis18, Trumpler23, and Trumpler20
• Near-infrared study of new embedded clusters in the Carina complex
• On the existence of young embedded clusters at high Galactic latitude