Star formation in UV-bright interacting galaxies

Galaxy interactions are known to drive interstellar gas toward the nuclear regions, thus triggering bursts of star formation. To investigate the relationship between galaxy interactions and the induced star formation, we obtained from the 40-inch telescope at Mt. Laguna U, B, V, and R images of NGC3395 & NGC3396 (an interacting pair) and NGC3991, NGC3994, & NGC3995 (an interacting trio), all of which exhibit strong UV emission known to be a signature of vigorous star formation. By comparing our multi-color data with star formation models, we can determine the age and strength of each star-forming region, and thus characterize the star-formation history of each object. One possibility is that interactions produce a “chain reaction” – one burst triggering another burst and so on – which should be discernible from the distribution of ages across the galaxy. We compare results from the NCG3991/4/5 trio with results from the NGC3395/6 pair