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10b. Circular (Ring) Spiral Arms and One-Armed Spirals

On page 10.3 we give examples where the spiral arms are wound almost into a detached circle. Morphologically this sub-category is obviously related to the case of one-armed spirals where the one arm can be seen through many turns. Such objects are illustrated on pages 10.5 and 10.6 with objects AM 2051-441 and AM 0552-324, respectively. On page 10.7 we show some examples of one-armed spirals where the arm is quite open and long. The examples then lead to spirals with two arms where one arm is much more pronounced than the other. On page 10.10, object AM 1239-402 is unusual in that it shows bright, narrow spiral arms wound with very shallow pitch angle. The last three objects on page 10.10 and the object on page 10.11 show double arms coming off one end of a bar. The phenomenon of narrow, parallel, double arms is quite striking. The object on page 10.11 is AM 1001-371 and is reproduced from a 4m CTIO plate (1399A). On page 10.12 the print of AM 0856-674 is also from an exposure (1386A) taken with the same telescope. This latter object is unusual for having very circular but nevertheless intersecting arms. The last page, 10.13, shows some miscellaneous peculiar spiral arms: AM 2117-400 is a barred spiral with strikingly different inner and outer arms, AM 1939-515 has a straight arm, perhaps due to an interaction with neighbouring companions. In object AM 2300-263 the western-most galaxy has an extremely faint, relatively large ring around it which should be studied on superposition plates or with linear detectors.