Abstract
High-resolution H I imaging observations of a heterogeneous sample of small galaxy groups are presented. The five galaxy groups studied show a broad range of individual H I properties: e.g. loose groups surrounding LGG 138 and the genuinely compact LGG 455 are identified; a massive ring of neutral gas is discovered encircling two luminous galaxies in the LGG 138 group; a galaxy-sized mass of H I is found in LGG 455 confined to an extragalactic cloud which exceeds the threshold density for star formation, yet is optically invisible; and the CCG 1 group is argued to be a chance alignment of Centaurus cluster galaxies. Global results of the study are that the deficit of H I flux in synthesis imaging data compared with single-dish data is put forward as a quantitative measure of the diffuseness of neutral gas in galaxy groups; several groups contain gas-poor galaxies that ordinarily would contain detectable quantities of H I - this is interpreted as being caused by an increased chance of gas-sweeping collisions in the group environment; and some evidence is found to support previous findings that compact groups preferentially occur in loose systems.
| Original language | English |
|---|---|
| Pages (from-to) | 859-876 |
| Number of pages | 18 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 324 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 11 Jul 2001 |
| Externally published | Yes |
Keywords
- Galaxies: evolution
- Galaxies: interactions
- Radio lines: galaxies
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