Recent star formation in interacting galaxies - I. Evidence from JHKL photometry

Abstract

We have carried out a survey using JHKL photometry to investigate recent star formation in interacting galaxies. The objective was to look for a K–L excess produced by ‘warm’ dust heated by a putative burst of star formation. We find K–L excesses suggesting that interactions induce starbursts with an efficiency approaching 100 per cent. The appearance of these inferred starbursts in interacting systems of different morphological types is qualitatively consistent with dynamical studies of galaxy interactions. However, the common occurrence of such starbursts shows that interactions have implications for the astrophysics of galaxies well beyond purely morphological effects.