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| Paper: |
Local Group High-Velocity Clouds: Status of the Evidence |
| Volume: |
240, Gas and Galaxy Evolution: A Conference in Honor of the 20th Anniversary of the VLA |
| Page: |
469 |
| Authors: |
Blitz, L. |
| Abstract: |
The evidence for locating the high-velocity clouds (HVCs) in the Local Group is summarized and evaluated. Recent measurements of the Hα surface brightness and metallicity of a number of HVCs appear to be fatal to the Galactic fountain as a significant contributor to the HVC phenomenon, but not to the existence of the fountain itself. Observations of extragalactic analogues to HVCs remain the sine qua non for deciding whether the Local Group hypothesis is viable, but the constraints based on existing surveys appear to be rather weak. Mg II quasar absorption lines restrict how many HVC analogues exist at intermediate redshift, depending on where these lines originate. It is concluded that the evidence remains ambiguous, none of the main hypotheses is fully consistent with all of the data, and the Local Group hypothesis remains a viable explanation for the HVC phenomenon. |
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