high-velocity clouds

high-velocity clouds

Small molecular and diffuse clouds, often far from the galactic plane, that have radial velocities differing significantly – sometimes up to 100 km s–1 – from those predicted by a simple Galactic rotation curve. Some may be associated with tidal effects, such as the Magellanic Stream (see Magellanic Cloud), while others are more likely due to galactic fountains.
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References in periodicals archive ?
Instead, astronomers suspect that some of them were created by high-velocity clouds (HVC).
Cloud punches hole in our galaxy
Also known as Smith's Cloud, it's one of thousands of high-velocity clouds of hydrogen gas flying around the outskirts of our Galaxy.
What makes galaxies keep on producing stars?
The Andromeda finding strengthens the case that the high-velocity clouds surrounding the Milky Way include remnant gas from the galaxy's origin, says Thilker.
Andromeda's building blocks
"The Smith Cloud is unique among high-velocity clouds because it is so clearly interacting with and merging with the Milky Way," said Felix J.
Giant Gas Cloud Colliding with Milky Way
The halo clouds are distinct from a larger population of 'high-velocity clouds' that also sail outside the galaxy.
Bursting 'bubbles' behind the origin of 'halo' gas clouds in our Galaxy
The fact is, many other "high-velocity clouds" are also falling toward the galactic plane with no one noticing except specialists.
Accurate distances are known for only a handful of high-velocity clouds. With the distance known, it was straightforward to calculate the cloud's dimensions--11,000 light-years long by 2,500 wide--and its position with respect to the Milky Way: some 9,000 light-years south of the galactic plane and 25,000 from the galactic center.
The mystery of the million-mass cloud
Complex H's radio emissions show that the object is much closer than high-velocity clouds and that its motion is tied to that of the Milky Way.
Astronomers had assumed the body was a so-called high-velocity cloud, a type of fast-moving mass of atomic hydrogen commonly found far from the galaxy.
Telescope spies a galactic satellite. (Astronomy)
Judging from models of structure formation in which small objects in the cosmos coalesce to form larger ones, "there ought to be clouds of dark matter and gas falling into our galaxy, and that's what we believe these high-velocity clouds are," he says.
Enigmatic gas clouds may fuel Milky Way
The origin of these so-called high-velocity clouds had been uncertain since they were first detected by Dutch astronomer Jan Oort in 1961.
High-velocity clouds explained
Astronomers believe that without this protective shell, the high-velocity cloud (HVC) known as the Smith Cloud would have disintegrated long ago when it first collided with the disk of our Galaxy.
Dark-Matter Jacket Saves Failed Dwarf Galaxy

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