High-velocity clouds

@inproceedings{Wakker1991HighvelocityC,
  title={High-velocity clouds},
  author={Bart P. Wakker},
  year={1991}
}
▪ Abstract High-velocity clouds (HVCs) consist of neutral hydrogen (HI) at velocities incompatible with a simple model of differential galactic rotation; in practice one uses vLSR 90 km/s to define HVCs. This review describes the main features of the sky and velocity distributions, as well as the available information on cloud properties, small-scale structure, velocity structure, and observations other than in 21-cm emission. We show that HVCs contain heavy elements and that the more prominent… 
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Global properties of the HI high velocity sky. A statistical investigation based on the LAB survey
Context. Since 1973, it has been known that some H i high velocity clouds (HVCs) have a core-envelope structure. Recent observations of compact HVCs confirm this, but more general investigations have…
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We investigate the hypothesis that compact high-velocity clouds (CHVC) are the 'missing' dwarf galaxies of the Local Group, by searching them for populations of resolved stars. To this end we…
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We present a catalog of high-velocity clouds (HVCs) from the Galactic All Sky Survey (GASS) of southern sky neutral hydrogen, which has 57 mK sensitivity and 1 km s{sup –1} velocity resolution and…
The High-Velocity Gas toward Messier 5: Tracing Feedback Flows in the Inner Galaxy
We present FUSE and STIS E140M observations of the post-AGB star ZNG 1 in the globular cluster Messier 5 ( -->l = 3.9°, -->b = + 47.7°; -->d = 7.5 kpc , -->z = + 5.3 kpc ). High-velocity absorption…
On the Critical Ionization Velocity Effect in Interstellar Space and Possible Detection of Related Continuum Emission
Interstellar neutral hydrogen (HI) emission spectra manifest several families of linewidths whose numerical values (34, 13, and 6 km/s) appear to be related to the critical ionization velocities…
A confirmed location in the Galactic halo for the high-velocity cloud ‘chain A’
The high-velocity clouds of atomic hydrogen, discovered about 35 years ago,, have velocities inconsistent with simple Galactic rotation models that generally fit the stars and gas in the Milky Way…
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References

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We present the first complete catalogue of high-velocity clouds (HVCs), followed by a classification of these clouds into complexes and populations. The catalogue will form the basis for comparisons…
Westerbork observations of high-velocity clouds. Discussion
Six high-velocity cloud fields were observed with 1' and 1 km s-1 resolution, using the Westerbork Synthesis Radio Telescope. The structures seen in earlier observations at 10' resolution break up…
The velocity structure of gas in the lines of sight to the Magellanic Clouds
CO and IRAS detection of an intermediate-velocity cloud
In the course of a radio survey of high-Galactic-latitude clouds, CO emission was detected at the position l = 210.8 deg and b = 63.1 deg with an LSR velocity of -39 km/sec. This molecular cloud…
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In this paper we continue our investigation of diffuse clouds in the interstellar medium with an analysis of the line of sight toward the star HD 215733, located in the Galactic halo some 1700 pc…
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Systematic emission and absorption surveys have been conducted for high-velocity H I in the direction of 63 bright continuum sources. High-velocity emisison is detected along 18 of these 63…
Structure of the interstellar medium in the Magellanic Clouds
Using optical and UV observations, the internal gas structure of Magellanic Clouds (MCs) was examined for clues to the recent evolution of the Magellanic System and further signs of this collision…
A SEARCH FOR DUST IN HIGH-VELOCITY CLOUDS
IRAS observations are used to look for infrared emission from dust in high-velocity clouds (HVCs). None of these clouds is detected. The upper limit that can be set on the IR emission per hydrogen…
Are there really intergalactic hydrogen clouds in the Sculptor group
High-sensitivity 21 cm observations of the region of the Sculptor group of galaxies reveal at least 30 H I clouds distributed over only the southern sector of the group. These new data add two…
Dynamics of the Outer Arm high-velocity cloud and the triaxiality of the Milky Way
Among high-velocity clouds of neutral hydrogen (HVCs) a so-called Outer Arm Cloud, often interpreted as a part of the general warp of the Milky Way disc, can be distinguished, which is located at 49°…
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