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STAR-FORMATION RATES OF INTERACTING GALAXIES.

The authors have obtained spectrophotometry for central regions of five interacting systems of galaxies chosen from the Arp Atlas of Peculiar Galaxies. The data are analyzed to derive star-formation rates for different epochs in the galaxies' histories. Oxygen abundances are estimated from emission-line ratios, and stellar population mixes are determined via spectral synthesis modeling. All systems have near-solar oxygen abundances. The authors find only one system, Arp 299, to be definitely undergoing a burst of star formation, while the remaining systems are found to be characterized by nearly constant rates of star formation and are not obviously different from noninteracting disk galaxies.