A description of the numerical codes shown in the seventh column of
the Catalogue is given below. The codes are substantially the same as
those listed in
Arp and Madore (1977).
They provide a fast means of
locating objects in a given Category without searching out key words
in the description. In many cases the object belongs simultaneously to
several Categories.
For instance, a galaxy with a jet (Code 7) may have apparent
companions (Code 8), one of which may be compact (Code 13) while the
dominant galaxy may be part of a wide group (Code 18). In this
respect, the numerical code can be supplementary to the description,
giving a concise means of noting additional peculiarities.
CODES
Numerical Brief General Description Relative
Code Percentage
1 Galaxies with interacting companion(s) 5.5
2 Interacting doubles (galaxies of comparable size)
12.6
3 Interacting triples 2.0
4 Interacting quartets 0.5
5 Interacting quintets 0.1
6 Ring galaxies (or morphologically similar objects)
3.1
7 Galaxies with (linear) jets 2.4
8 Galaxies with apparent companion(s) 11.5
9 M51-types (companion at end of spiral arm) 2.0
10 Galaxies with peculiar spiral arms 4.1
11 Three-armed spirals and multiple-armed spirals
0.5
12 Peculiar disks (major asymmetry or deformation)
2.8
13 Compact (very high-surface-brightness) galaxies
6.4
14 Galaxies with prominent or unusual dust absorption
1.6
15 Galaxies with tails, loops of material or debris
3.5
16 Irregular or disturbed,(apparently isolated) galaxies
4.2
17 Chains (four or more galaxies aligned) 4.0
18 Groups (four or more galaxies not aligned) 4.9
19 Clusters (only very conspicuous, rich systems)
1.6
20 Dwarf galaxies (low surface brightness) 6.8
21 Stellar objects with associated nebulosity 0.7
22 Miscellaneous (rare or distinctive objects) 1.4
23 Close pairs (not visibly interacting) 11.4
24 Close triples (not visibly interacting) 5.6
25 Planetary Nebulae 0.9