Abstract
The radio source Sgr A and neighbouring features have been mapped at a frequency of 843 MHz with a beamwidth of 43 × 87 arcsec. Comparisons have been made with published maps of comparable resolution at different frequencies in order to differentiate thermal and nonthermal regions. The arc feature to the north of Sgr A appears to consist of low-temperature ionized hydrogen and to extend partly over Sgr A itself causing patchy absorption at low frequencies; there is some evidence that the hydrogen in the arc has been expelled from the galactic nucleus. Previous suggestions that Sgr A East is a supernova remnant have been examined and the interpretation is found to be quite likely, but not compelling. The diffuse component of Sgr A West appears to be due entirely to ionized hydrogen surrounding the nucleus.
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Mills, B.Y., Drinkwater, M.J. The radio spectra of galactic centre features. J. Astrophys. Astr. 5, 43–53 (1984). https://doi.org/10.1007/BF02714971
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DOI: https://doi.org/10.1007/BF02714971