It is known that the SA is not complete to its stated magnitude limit of mpg = 13m.2 but becomes progressively more incomplete as this magnitude level is approached. A study of the incompleteness (Sandage, Tammann, and Yahil, 1979) suggests that the fraction f(m) of a complete sample in fact contained in the SA is well represented by
where m is the magnitude in the BT system.
In this representation, the progressive incompleteness of the SA is
a rapid function of m, as shown in figure 6 of the above-stated
reference, where the equation is compared with counts of E and S0
galaxies contained in fainter catalogs. Note that at m =
12m, f (m) = 1, while at m
As an aid toward the eventual revision of the SA to a more complete
magnitude-limited catalog, we list in Appendix A those galaxies that
should be included to a limit of BT
12m.7, f (m)
is only 0.5.
13m.2, obtained by
converting the
magnitudes in the Nilson and the Zwicky catalogs to the
BT system. In
Appendix B, we list particular dwarf galaxies (many of which are well
known) that should also be included. These lists are of course
incomplete, if only because they are predominantly for the northern
hemisphere. It should also be cautioned that the types and magnitudes
of these candidate galaxies are more uncertain than those in the main table.