3. Data from the submm-range
For a comparison with data from other telescopes, we have to convert measured peak flux densities to integrated fluxes for each source which requires knowledge of the source sizes. The size of the thermal Bremsstrahlung source is determined by interferometric observations at short cm-wavelengths. This value was used as an approximation for frequencies below 100 GHz where the contribution from dust emission is small. At 300 GHz, dust emission dominates the integrated spectrum and we used the extent of the dust for the determination of total fluxes. In Table 2 we give the extent of the sources at different frequencies. The integrated flux densities were calculated by assuming both a gaussian shape of the sources and a linear increase of the source sizes with frequency. A constant source size was assumed above that frequency at which the dust emission clearly dominates the continuum spectrum. For W 3(OH) and K 3-50A the corresponding frequencies were found to be 250 Ghz and 400 GHz, respectively. The integrated flux was then simply calculated as
where in the submm regime for W 3(OH) and for K 3-50A.
Table 1. Source positions
© European Southern Observatory (ESO) 1998
Online publication: September 30, 1998