Radio Continuum and CO Line Emissions in the Galactic Center Region

Abstract A comparison of radio continuum maps at 10 GHz and molecular-line emission data has been made for the central region of the Galaxy. Thermal continuum sources (H II regions) are generally associated with molecular clouds. However, the peak positions of the continuum and molecular features tend to spatially avoid each other. The young star-forming region Sgr B2 is associated with a dense compact molecular cloud. The neighbouring Hn region Sgr B1 is enclosed by a molecular shell. This shell is in contact with the Sgr B2 molecular complex, suggesting that star formation in Sgr B2 has been triggered by an expanding shell driven by Sgr B1. The H II regions near G–0.27–0.03 are surrounded by molecular arcs, while no dense clouds are associated, suggesting that the star-forming activity has passed its peak in these regions.