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Published online by Cambridge University Press: 12 April 2016
We report the results of a detailed statistical analysis of the Mid and Far IR (MIR/FIR) emission properties in a mixed morphology (E+S) sample of galaxy pairs from the Karachentsev (1972) Catalogue. The sample is large and diverse enough (≃ 130 pairs) to permit discrimination of pairs by morphological types and interaction classes. It samples a large enough volume to enable a non-parametric estimate of a Far-Infrared Luminosity Function (FIRLF). We find average factors of 3 and 5 enhancement in FIR and 25μm luminosities of the late-type pair components relative to an isolated galaxy control sample from Karachentseva (1973) Catalogue. This is interpreted as the MIR/FIR signature of the link between interaction and star formation. Although the spirals in (E+S) pairs fail to show a trend towards higher FIR luminosity with decreasing companion separation, a high-order comparison that takes into account information on the interaction classes, morphological types and the HI content suggests that:
• a clear correlation between the IR luminosities and interaction classes is present suggesting that a subsample of the (E+S) pairs is more closely related to recent events of star formation,
• the ratio of present to past star formation (as measured by the IR luminosities scaled to LB luminosity), increases measurably along the sequence Sa-Sc in paired spirals,
• no Hɪ depletion in the star formation-enhanced spirals in mixed pairs is found, and
• the high mass (M ≥ 10 M⊙) star formation rate (SFR) in paired Sc spirals is higher than that of the isolated Sc’s by a factor ~ 2 – 3.