Cool Gas in the Magellanic Stream

Abstract

We present the first direct detection of cold atomic gas in the Magellanic Stream, through 21 cm line absorption toward a background radio source, J0119 - 6809, using the Australia Telescope Compact Array. Two absorption components were identified at heliocentric velocities 218.6 km/s and 227.0 km/s, with optical depths of tau ~ 0.02. The corresponding H I emission region has a column density in excess of 2 x 10^20 cm^{-2}. The inferred spin temperature of the emitting gas is ~70 K. We failed to find cool gas in observations of three other radio continuum sources. Although we have definitively detected cool gas in the Stream, its spin temperature is higher than similar components in the LMC, SMC and Bridge, and its contribution to the total H I density is probably lower. No corresponding 12CO(J = 1 -> 0) or dust appears to be associated with the cool gas, suggesting that the cloud is not forming stars.

References in corpus (10)

• Are the Magellanic Clouds on their First Passage about the Milky Way?
• The Proper Motion of the Large Magellanic Cloud using HST
• 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 gravitational and hydrodynamical interaction between the LMC and the Galaxy
• N-body simulations of the Magellanic Stream
• Metallicity and Physical Conditions in the Magellanic Bridge
• The early evolution of tidal dwarf galaxies
• Detection of Carbon Monoxide within the Magellanic Bridge

Cited by in corpus (13)

• The Role of Dwarf Galaxy Interactions in Shaping the Magellanic System and Implications for Magellanic Irregulars
• The Magellanic Stream: Circumnavigating the Galaxy
• Exploring the Origin and Fate of the Magellanic Stream with Ultraviolet and Optical Absorption
• The COS/UVES Absorption Survey of the Magellanic Stream: I. One-Tenth Solar Abundances along the Body of the Stream
• New 20-cm radio-continuum study of the small Magellanic cloud: Part I - Images
• Probing the Structure and Kinematics of the transition Layer between the Magellanic Stream and the Halo in HI
• The Distance and Properties of Hydrogen Clouds in the Leading Arm of the Magellanic System
• Cold HI ejected into the Magellanic Stream
• First Detection of HCO${}^{+}$ Absorption in the Magellanic System
• A Compact High Velocity Cloud near the Magellanic Stream: Metallicity and Small-Scale Structure
• A neutral hydrogen absorption study of cold gas in the outskirts of the Magellanic Clouds using the GASKAP-HI survey
• Hydrodynamics of Clustered Clouds: Drafting, Survival, Condensation, and Ablation
• The orbital dynamics of the LMC and SMC about the Milky Way