The Distance and Properties of Hydrogen Clouds in the Leading Arm of the Magellanic System

Abstract

We present a high-resolution study of five high-velocity clouds in the Magellanic Leading Arm region. This is a follow-up study of our widefield Parkes survey of the region in order to probe the multiphase structures of the clouds and to give an insight to their origin, evolution and distance. High-resolution data were obtained from the Australia Telescope Compact Array. By combining with single-dish data from the Galactic All-Sky Survey (GASS), we are able to probe compact and diffuse emission simultaneously. We identify resolved and unresolved clumps. Physical parameters were derived for both diffuse structure and compact clumps. The latter are cold with typical velocity linewidths of 5 km/s. We find a gradient in thermal halo pressure, hydrogen density and HI column density of HVC as a function of Galactic latitude. This is possibly the first observational evidence of varying distance in the Leading Arm region, with the leading part of the Leading Arm (LA II and III) probably being closer to the Galactic disc than the trailing end (LA I).

arXiv comment17 pages, 11 figures, accepted for publication in MNRAS

References in corpus (33)

• Dark Matter Substructure in Galactic Halos
• Where are the missing galactic satellites?
• An eclipsing binary distance to the Large Magellanic Cloud accurate to 2 per cent
• 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
• High Velocity Clouds: Building Blocks of the Local Group
• GASS: The Parkes Galactic All-Sky Survey. I. Survey Description, Goals, and Initial Data Release
• The Australia Telescope Compact Array Broadband Backend (CABB)
• VLA HI Observations of Gas Stripping in the Virgo Cluster Spiral NGC 4522
• The Parkes HI Survey of the Magellanic System
• GASS: The Parkes Galactic All-Sky Survey. II. Stray-Radiation Correction and Second Data Release
• Ram Pressure Stripping of the Large Magellanic Cloud's Disk as a Probe of the Milky Way's Circumgalactic Medium
• A retrospective view of Miriad
• FUSE Observations of Atomic Abundances and Molecular Hydrogen in the Leading Arm of the Magellanic Stream
• Constraining the orbital history of the Magellanic Clouds: A new bound scenario suggested by the tidal origin of the Magellanic Stream
• Gas Dynamics and Star Formation in the Galaxy Pair NGC1512/1510
• A Targeted Survey for HI Clouds in Galaxy Groups
• The many streams of the Magellanic Stream
• Deep H I observations of the compact high-velocity cloud HVC125+41-207
• An Interaction of a Magellanic Leading Arm High Velocity Cloud with the Milky Way Disk
• Where are the High Velocity Clouds in Local Group Analogs?
• Head-Tail Clouds: Drops to Probe the Diffuse Galactic Halo
• Effelsberg HI observations of compact high-velocity clouds
• The four leading arms of the Magellanic Cloud system
• On the neutral gas content of nine new Milky Way satellite galaxy candidates
• The Magellanic Stream and Debris Clouds
• Recent Star Formation in the Leading Arm of the Magellanic Stream
• Local ultra faint dwarves as a product of Galactic processing during a Magellanic group infall
• GASS High Velocity Clouds in the Region of the Magellanic Leading Arm
• HI Observations of an Ultra-Compact High-Velocity Cloud
• Physical properties of two compact high-velocity clouds possibly associated with the Leading Arm of the Magellanic System
• Cool Gas in the Magellanic Stream

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