The many streams of the Magellanic Stream

Abstract

We present results from neutral hydrogen (HI) observations of the tip of the Magellanic Stream (MS), obtained with the Arecibo telescope as a part of the on-going survey by the Consortium for Galactic studies with the Arecibo L-band Feed Array. We find four large-scale, coherent HI streams, extending continously over a length of 20 degrees, each stream possessing different morphology and velocity gradients. The newly discovered streams provide strong support for the tidal model of the MS formation by Connors et al. (2006), which suggested a spatial and kinematic bifurcation of the MS. The observed morphology and kinematics suggest that three of these streams could be interpreted as a 3-way splitting of the main MS filament, while the fourth stream appears much younger and may have originated from the Magellanic Bridge. We find an extensive population of HI clouds at the tip of the MS. Two thirds of clouds have an angular size in the range 3.5'--10'. We interpret this as being due to thermal instability, which would affect a warm tail of gas trailing through the Galactic halo over a characteristic timescale of a few Myrs to a few hundred Myrs. We show that thermal fragments can survive in the hot halo for a long time, especially if surrounded by a <10^6 K halo gas. If the observed clumpy structure is mainly due to thermal instability, then the tip of the MS is at a distance of ~70 kpc. A significant fraction of HI clouds at the tip of the MS show multi-phase velocity profiles, indicating the co-existence of cooler and warmer gas.

Accepted by ApJ

References in corpus (21)

• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• The Arecibo Legacy Fast ALFA Survey: I. Science Goals, Survey Design and Strategy
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• Highly-Ionized High-Velocity Gas in the Vicinity of the Galaxy
• Thermal condensation in a turbulent atomic hydrogen flow
• N-body Simulations of the Small Magellanic Cloud and the Magellanic Stream
• The Magellanic Stream, High-Velocity Clouds and the Sculptor Group
• Is the SMC Bound to the LMC? The HST Proper Motion of the SMC
• The Origin of the Magellanic Stream and Its Leading Arm
• The Parkes HI Survey of the Magellanic System
• The gravitational and hydrodynamical interaction between the LMC and the Galaxy
• The WSRT wide-field HI survey: II. Local Group features
• N-body simulations of the Magellanic Stream
• Atomic Hydrogen Gas in Dark-Matter Minihalos and the Compact High Velocity Clouds
• A high sensitivity HI survey of the sky at delta < -25 deg Final data release
• The small-scale structure of the Magellanic Stream
• First results from the Arecibo Galactic HI Survey: the disk/halo interface region in the outer Galaxy
• High-resolution imaging of compact high-velocity clouds (II)
• On the Two-Phase Structure of Protogalactic Clouds
• A New Technique for Heterodyne Spectroscopy: Least-Squares Frequency Switching (LSFS)
• Mini High Velocity Clouds

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