Open AccessA study of neutral hydrogen in five small galaxy groups
Author(s) -
Barnes D. G.,
Webster R. L.
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04273.x
Subject(s) - physics , galaxy group , astrophysics , galaxy , centaurus a , interacting galaxy , astronomy , lenticular galaxy , star formation , galaxy merger , galaxy cluster , brightest cluster galaxy , galaxy formation and evolution , radio galaxy
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.