Smith's Cloud: A High-velocity Cloud Colliding with the Milky Way

Abstract

New 21cm HI observations made with the Green Bank Telescope show that the high-velocity cloud known as Smith's Cloud has a striking cometary appearance and many indications of interaction with the Galactic ISM. The velocities of interaction give a kinematic distance of 12.4 +/-1.3 kpc, consistent with the distance derived from other methods. The Cloud is >3 x 1 kpc in size and its tip at (l,b)=(39 deg,-13 deg) is 7.6 kpc from the Galactic center and 2.9 kpc below the Galactic plane. It has greater than 10^6 M solar masses in HI. Its leading section has a total space velocity near 300 km/s, is moving toward the Galactic plane with a velocity of 73+/-26 km/s, and is shedding material to the Galaxy. In the absence of drag the Cloud will cross the plane in about 27 Myr. Smith's Cloud may be an example of the accretion of gas by the Milky Way needed to explain certain persistent anomalies in Galactic chemical evolution.

Accepted for publication in Astrophysical Journal Letters

References in corpus (19)

• Multi-Phase Galaxy Formation: High Velocity Clouds and the Missing Baryon Problem
• High Velocity Clouds: Building Blocks of the Local Group
• Distances to Galactic high-velocity clouds. I. Cohen Stream, complex GCP, cloud g1
• H_alpha Emission from High-Velocity Clouds and their Distances
• Distances to Galactic high-velocity clouds. Complex C
• An Accurate Distance to High-Velocity Cloud Complex C
• The Smith Cloud: HI associated with the Sgr dwarf?
• Discovery of a Population of HI Clouds in the Galactic Halo
• High Velocity Rain: The Terminal Velocity of Model of Galactic Infall
• Deuterium astration in the local disc and beyond
• A Very Sensitive 21cm Survey for Galactic High-Velocity HI
• Deep H I observations of the compact high-velocity cloud HVC125+41-207
• Reconstructing Deconstruction: High-Velocity Cloud Distance Through Disruption Morphology
• The Ophiuchus Superbubble: A Gigantic Eruption from the Inner Disk of the Milky Way
• An Interaction of a Magellanic Leading Arm High Velocity Cloud with the Milky Way Disk
• High Velocity Cloud Complex H: A Satellite of the Milky Way in a Retrograde Orbit?
• Ionized Gas in the First 10 kpc of the Interstellar Galactic Halo
• Potential Condensed Fuel for the Milky Way
• On the origin of anomalous velocity clouds in the Milky Way

Cited by in corpus (73)

• GASS: The Parkes Galactic All-Sky Survey. I. Survey Description, Goals, and Initial Data Release
• The Direct Detection of Cool, Metal-Enriched Gas Accretion onto Galaxies at z ~ 0.5
• GASKAP -- The Galactic ASKAP Survey
• Magnetic Field Morphology in Interstellar Clouds with the Velocity Gradient Technique
• On the Metallicity and Origin of the Smith High-Velocity Cloud
• Modelling the HI halo of the Milky Way
• Phased Array Feed Calibration, Beamforming and Imaging
• Cold gas outflows from the Small Magellanic Cloud traced with ASKAP
• Ionized Gas in the Smith Cloud
• Measuring turbulence in the ISM by comparing N(HI;Lya) and N(HI;21cm)
• The impact of stellar and AGN feedback on halo-scale baryonic and dark matter accretion in the EAGLE simulations
• Hubble-COS Observations of Galactic High-Velocity Clouds: Four AGN Sight Lines through Complex C
• Properties and Origin of the High-Velocity Gas Toward the Large Magellanic Cloud
• The Smith Cloud: high-velocity accretion and dark-matter confinement
• The Magellanic Stream: break up and accretion onto the hot Galactic corona
• The Neutral Hydrogen Bridge between M31 and M33
• Cloudy with A Chance of Rain: Accretion Braking of Cold Clouds
• Magnetized Gas in the Smith High Velocity Cloud
• The Smith Cloud and its dark matter halo: Survival of a Galactic disc passage
• Gas Accretion onto the Milky Way
• Anomalous HI in NGC 2997
• A Low Metallicity Molecular Cloud In The Lower Galactic Halo
• HI Observations of the Asymptotic Giant Branch Star X Herculis: Discovery of an Extended Circumstellar Wake Superposed on a Compact High-Velocity Cloud
• Constraining the Magnetic Field of the Smith High Velocity Cloud using Faraday rotation
• Magnetized High Velocity Clouds in the Galactic Halo: A New Distance Constraint
• Collisions between Dark Matter Confined High Velocity Clouds and Magnetized Galactic Disks: The Smith Cloud
• Present-day Galactic Evolution: Low-metallicity, Warm, Ionized Gas Inflow Associated with High-Velocity Cloud Complex A
• Mass, Morphing, Metallicities: The Evolution of Infalling High Velocity Clouds
• Disentangling the Faraday rotation sky
• Simulating Gas Inflow at the Disk-Halo Interface
• Searching for Dark Matter Annihilation in the Smith High-Velocity Cloud
• Search for Diffuse Neutral Hydrogen and HI Clouds in the NGC 2403 Group
• A Search For Star Formation in the Smith Cloud
• The high-velocity cloud complex Galactic Center Negative as seen by EBHIS and GASS. I. Cloud catalog and global properties
• The Smith Cloud: surviving a high speed transit of the Galactic disc
• Discovery of two embedded clusters with WISE in the high Galactic latitude cloud HRK 81.4-77.8
• The Effect of Mixing on the Observed Metallicity of the Smith Cloud
• Magnetic field draping around clumpy high-velocity clouds in galactic halo
• Interstellar magnetic cannon targeting the Galactic halo : A young bubble at the origin of the Ophiuchus and Lupus molecular complexes
• High-energy radiation from collisions of high velocity clouds and the Galactic disk
• Extraplanar H II Regions in Spiral Galaxies. I. Low-Metallicity Gas Accreting through the Disk-Halo Interface of NGC 4013
• The Origin of Neutral Hydrogen Clouds in Nearby Galaxy Groups: Exploring the Range Of Galaxy Interactions
• Caught in the Act: A Metal-Rich High-Velocity Cloud in the Inner Galaxy
• H$\alpha$ Distances to the Leading Arm of the Magellanic Stream
• Far-infrared excess emission as a tracer of disk-halo interaction
• VERA astrometry toward the Perseus arm gap
• Warm gas accretion onto the Galaxy
• The First Distance Constraint on the Renegade High Velocity Cloud Complex WD
• Exploring Hydrodynamic Instabilities along the Infalling High-Velocity Cloud Complex A
• The high-velocity clouds above the disk of the outer Milky Way: misty precipitating gas in a region roiled by stellar streams
• Simulating the impact of the Smith Cloud
• Modeling the X-rays Resulting from High Velocity Clouds
• The Gould's Belt Distances Survey
• DIISC-II: Unveiling the Connections between Star Formation and ISM in the Extended Ultraviolet Disk of NGC 3344
• Turn-off of Deuterium Astration in the Recent Star Formation of the Galaxy Disk
• Synchrotron Emission from Dark Matter in Galactic Subhalos. A Look into the Smith Cloud
• A Spitzer-MIPS search for dust in compact high-velocity HI clouds
• Three-Dimensional Orientation of Compact High Velocity Clouds
• Discovery and Follow-up of a Nearby Galaxy from the Arecibo Zone of Avoidance Survey
• Properties of 3D HI Filaments in the Smith High Velocity Cloud
• A Component of the Smith High Velocity Cloud Now Crossing the Galactic Plane
• A new delivery route to Galactic Nuclei: Warm halo cloud impacts
• Tracing dense and diffuse neutral hydrogen in the halo of the Milky Way
• Neutral Gas Accretion onto Nearby Galaxies
• Accretion Onto the Milky Way: The Smith Cloud
• Estimating the Fuel Supply Rate on the Galactic Disk from High Velocity Clouds (HVCs) Infall
• Resolving the formation of cold HI filaments in the high velocity cloud complex C
• Millimeter-wave CO and SiO Observations toward the Broad-velocity-width Molecular Feature CO 16.134-0.553: a Smith cloud scenario?
• Interaction Between Rogue HI Clouds and the Magnetic Field High Above the Galaxy
• Simulating High-Velocity Clouds in the Observational Plane: An Initial Study with the Smith Cloud
• Ionized Gas in the Smith Cloud
• Gamma rays from reaccelerated cosmic rays in high velocity clouds colliding with the Galactic disk
• On the origin of gaseous galaxy halos - Low-column density gas in the Milky Way halo