LARGE-SCALE STRUCTURE OF THE IONIZED-GAS IN THE MAGELLANIC CLOUDS

Calibrated Hα CCD images taken with the "Parking Lot Camera" are used to investigate the large scale properties of the ionized gas in the Magellanic Clouds. The integrated Hα luminosity, star formation, and the large-scale diffuse emission are studied and compared with other galaxies. The diffuse gas component accounts for 30%-40% of the total Hα emission in both galaxies. The integrated star formation rates and the fraction of diffuse emission are typical for Magellanic irregular galaxies. The Hα maps are used to derive a set of physical parameters for the known supergiant shells in the LMC and SMC. The Hα emission distribution have also been compared to the distribution of H I column density. Evidence for a star formation threshold is discussed.