Far-infrared (120-300 micron) observations of Southern H II regions

Observations of three southern H II regions, namely RCW 57, RCW 108, and RCW 122, in a 120-300 micron wavelength band are presented. The intensity maps, covering an area greater than 15×20 arcmin with an angular resolution of about 1 arcmin, are presented for each source and compared with the observations in other bands to draw conclusions on temperatures, luminosities, optical depths, and the dust emissivity law. It is found that the IR luminosity of these sources can be explained as being due to zero-age-main-sequence early-type stars energizing the clouds. The wavelength dependence of the emissivity for the submillimeter-emitting dust, in RCW 57 and RCW 122, is found to be substantially flatter than that usually found for H II regions