IUE spectra of clumpy irregular galaxies

Abstract

IUE spectra at short wavelengths were obtained for two clumpy irregular galaxies, Mkn 8 and Mkn 325. Clumps could be resolved across the slit. Statistics now available on 10 clumps show that, on average, each clump radiates 100 times more at 155 nm than the giant H II region 30 Doradus and contains 0.00007 early-type stars. This confirms the hypothesis that clumps may be hyperactive H II complexes and that clumpy irregulars are galaxies in which star formation occurs on an exceptional scale.