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Statistical Properties of the Emission in Mixed-Morphology (E+S) Pairs. I. Optical Results
We present a statistical analysis of the optical emission properties fora mixed-morphology (E+S) sample of galaxy pairs. The sample is large anddiverse enough (~150 pairs) to permit discrimination of pairs bymorphological types. It samples a large enough volume of space tojustify derivation of the optical luminosity function. We find anaverage factor of 1.6 enhancement in the optical luminosity of thelate-type pair components relative to an isolated galaxy control sample.This is interpreted as the optical signature of the interaction-starformation connection. We find a complete absence of dwarf pairs(M_Zw>=-17.0) that is probably related to a corresponding lack ofisolated 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 toshow a trend toward higher luminosity with decreasing companionseparation. A first-order comparison of galaxy type distributionsbetween our pair and isolated samples suggests that (1) pairs show anexcess 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 anddynamical explanations for (1) the observed (E+S) spiral-componentluminosity excess and (2) the morphology excesses/deficits.
| The CfA Redshift Survey: Data for the NGP +36 Zone
We have assembled redshifts for a complete sample of 719 galaxies withm_zw_ <= 15.5 in the declination range 32.5^deg^ <= δ <=38.5^deg^ and right ascension range 8^h^ <= α <= 17^h^. Wehave determined morphological types for all galaxies in the magnitudelimited sample by direct inspection of the POSS-O plates. 576 of theredshifts are measurements from Mount Hopkins, and 405 are newredshifts. We also include new redshifts for 77 fainter galaxies in thesame strip.
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