The differences of star formation history between merging galaxies and field galaxies in the early data release of the SDSS

Based on the catalog of merging galaxies in the Early Data Release of the Sloan Digital Sky Survey, the differences of star-formation history between merging galaxies and field galaxies were studied statistically by means of three spectroscopic indicators: the 4000-angstrom break strength, the Balmer absorption-line index, and the specific star formation rate. It is found that for early-type merging galaxies the interactions will not induce any significant enhancement of the star-formation activity because of its stability and lack of cool gas. On the other hand, late-type merging galaxies always in general display more active star formation than field galaxies on different timescales within about 1 Gyr. We also conclude that the mean stellar ages of late-type merging galaxies are younger than those of late-type field galaxies.