Multiwavelength observations of N 66 in the SMC: unveiling photodissociation interfaces and star formation

We present new observations of the major star-forming region N66 in the Sma ll Magellanic Cloud and of its surroundings, which add to those presented i n Contursi et al. (2000, Paper I). High-sensitivity CO observations allowed the detection of molecular gas associated with the H II region, for which a high-resolution image in [O III] lambda 5007 is presented. We also presen t images in the v(1-0) S(1) line of H-2 at 2.12 mu m and in the adjacent co ntinuum. This material reveals an interesting photodissociation region. We show that the molecular gas that has not yet been photodissociated by the U V radiation of the stars is in hot, dense clumps with a very small surface filling factor. We discovered several embedded stars or stellar association s, and suggest that three successive stellar generations have already taken place in less than 3 million years.