Study of star formation in RCW 106 using far-infrared observations

High-resolution far-infrared observations of a large area of the star-formi ng complex RCW 106 obtained using the TIFR 1-m balloon-borne telescope are presented. Intensity maps have been obtained simultaneously in two bands ce ntred around 150 and 210 mum. Intensity maps have also been obtained in the four IRAS bands using HIRES-processed IRAS data. From the 150- and 210-mum maps, reliable maps of dust temperature and optical depth have been genera ted. The star formation in this complex has occurred in five linear sub-clu mps. Using the map at 210 mum, which has a spatial resolution superior to t hat of IRAS at 100 mum, 23 sources have been identified. The spectral energ y distribution (SED) and luminosity of these sources have been determined u sing the associations with the IRAS maps. The luminosity distribution of th ese sources has been obtained. Assuming these embedded sources to be zero-a ge main-sequence stars and using the mass-luminosity relation for these, th e power-law slope of the initial mass function is found to be -1.73 +/-0.5. This index for this very young complex is about the same as that for more evolved complexes and clusters. Radiation transfer calculations in spherica lly symmetric geometry have been undertaken to fit the SEDs of 13 sources w ith fluxes in both the TIFR and the IRAS bands. From this, the r(-2) densit y distribution in the envelopes is ruled out. Finally, a correlation is see n between the luminosity of embedded sources and the computed dust masses o f the envelopes.