High-Velocity Cloud Complex H: A Satellite of the Milky Way in a Retrograde Orbit?
@article{Lockman2003HighVelocityCC, title={High-Velocity Cloud Complex H: A Satellite of the Milky Way in a Retrograde Orbit?}, author={Felix J. Lockman}, journal={The Astrophysical Journal}, year={2003}, volume={591} }
Observations with the Green Bank Telescope of 21 cm H I emission from the high-velocity cloud complex H suggest that it is interacting with the Milky Way. A model in which the cloud is a satellite of the Galaxy in an inclined, retrograde circular orbit reproduces both the cloud's average velocity and its velocity gradient with latitude. The model places complex H at R = 33 ± 9 kpc from the Galactic center on a retrograde orbit inclined ≈45° to the Galactic plane. At this location, it has a mass…
38 Citations
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References
SHOWING 1-10 OF 29 REFERENCES
Discovery of a Population of H I Clouds in the Galactic Halo (Accepted for Publication in the Astrophysical Journal Letters) (Preprint - October 14, 2002)
- Physics
- 2002
A population of discrete H I clouds in the halo of the inner Galaxy has been discovered in 21 cm observations made with the Green Bank Telescope. The halo clouds are seen up to 1.5 kpc from the…
High-Velocity Clouds: Building Blocks of the Local Group
- Physics
- 1999
We suggest that the high-velocity clouds (HVCs) are large clouds, with typical diameters of 25 kpc, containing 3×107 M☉ of neutral gas and 3×108 M☉ of dark matter, falling onto the Local Group;…
A Lower Limit to the Distance of High-Velocity Cloud Complex H
- Physics
- 1998
We derive a lower limit for the distance of the high-velocity cloud (HVC) complex H, which is a structure covering 480 square degrees on the sky and is centered on l = 131°, b = 1°. Considering the…
Where are the high velocity clouds
- Physics
- 2001
Recent observations of high-velocity clouds (HVCs) have revealed compression fronts and tail-shaped features of H I, suggesting that they are interacting with an external medium. We perform…
Infrared Search for Young Stars in H I High-Velocity Clouds
- Physics
- 1997
We have searched the IRAS Point Source Catalog and HIRES maps for young stellar objects (YSOs) in the direction of five H I high-velocity clouds (HVCs). In agreement with optical searches in the…
Dynamical evolution of high velocity clouds in the intergalactic medium
- Physics
- 2002
Hi observations of high-velocity clouds (HVCs) indicate, that they are interacting with their ambient medium. Even clouds located in the very outer Galactic halo or the intergalactic space seem to…
On the Distance Determination and Ionization of the High-Velocity Clouds
- Physics
- 1994
We present a study of the ionization and thermal structure of neutral hydrogen clouds located in the Galactic halo, immersed in the extragalactic background radiation field, and supposed to be in…
The disruption of nearby galaxies by the Milky Way
- Physics
- 1998
Interactions between galaxies are common and are an important factor in determining their physical properties such as position along the Hubble sequence and star-formation rate. There are many…
H I Fine Structure in Magellanic Tidal Debris
- Physics
- 2002
We report on H I observations with the Australia Telescope and the Parkes telescope of one of the cores of the high-velocity cloud (HVC) WW 187 (also known as HVC 287+23+240 and HVC 287.5+22.5+240).…
The Oldest Stars of the Extremely Metal-Poor Local Group Dwarf Irregular Galaxy Leo A*
- Physics
- 2002
We present deep Hubble Space Telescope (HST) single-star photometry of Leo A in B, V, and I. Our new field of view is offset from the centrally located field observed by Tolstoy et al. in order to…