A high-resolution study of SGR-B2 at CM-wavelengths

The radio source Sgr-B2 was studied with the radio telescope of the USSR Academy of Sciences, RATAN-600, at wavelengths 13, 8.2, 3.9, 2.08, and 1.38 cm. The brightness distributions obtained allow us to defined spectra of individual components and to revise a total spectrum of the source itself. It was shown that the source contains no less than four ultracompact details with electron densities exceeding 2×10⁴ cm^–3. An extended detail with a flux density at 1.38 cm equal to 12.2 f.u. and an angular size 58 arc sec was found in a nuclear region. Excitation parameters of all compact details were shown to correspond to stars of a spectral type earlier than O6 (U60). A relation (logN _e –logd) for all Hii regions in the field around Sgr-B2, including G 0.6-0.0 and G 0.5-0.0, was constructed and shown to be nearly linear, with a slope –1.2.