SIMBAD references

We present a statistical analysis of the optical emission properties for a mixed-morphology (E+S) sample of galaxy pairs. The sample is large and diverse enough (∼150 pairs) to permit discrimination of pairs by morphological types. It samples a large enough volume of space to justify derivation of the optical luminosity function. We find an average factor of 1.6 enhancement in the optical luminosity of the late-type pair components relative to an isolated galaxy control sample. This is interpreted as the optical signature of the interaction-star formation connection. We find a complete absence of dwarf pairs (M_Zw≥-17.0) that is probably related to a corresponding lack of isolated E/S0 dwarf galaxies in the control sample. The spirals in (E+S) and (S+S) pairs show similar levels of optical enhancement but fail to show a trend toward higher luminosity with decreasing companion separation. A first-order comparison of galaxy type distributions between our pair and isolated samples suggests that (1) pairs show an excess of elliptical and early-type spiral (Sa-b) components and (2) corresponding deficit of S0s and late-type spirals in the ``E'' and ``S'' pair components, respectively. We consider both possible bias and dynamical explanations for (1) the observed (E+S) spiral-component luminosity excess and (2) the morphology excesses/deficits.