The luminosity function (LF) of the M 81 group has been constructed from total B magnitudes given in Table 1 (click here) and is shown in Fig. B1 (click here). Possible members are included - however not those suspected to be cirrus clouds (cf. Appendix A). The absolute magnitude scale is based on a distance of 4 Mpc for the M 81 group, corresponding to m-M=28.01. The limit of completeness for this LF depends on the depth of the photographic survey of Börngen et al. (1982), which is not well defined. We guess a magnitude of completeness is .
For comparison, we also show the LF of the LG in Fig. B1 (click here). The data are taken from Côté (1995), who converted the Van Den Bergh (1992) V magnitudes into B magnitudes. The Van Den Bergh (1992) LF includes all LG members within a distance of 1 Mpc. The estimated limit of completeness here is . Besides a factor of difference in richness - the M 81 group being richer than the LG - the two LF's are clearly compatible with each other.
Figure B1: Luminosity function of the M 81 group of galaxies (solid line) compared with that of the Local Group (shaded)