Structural details of the Sagittarius A complex - evidence for a large-scale poloidal magnetic field in the Galactic center region

Detailed radio observations of the Sagittarius A complex are presented and discussed. The evidence is consistent with a large-scale poloidal magnetic field lying at the Galactic center. Arguments are made in favor of the suggestion that ionized gas is flowing out isotropically from the nucleus, and that Sgr A East is located behind Sgr A West. The question whether Sgr East is a supernova remnant or the result of energetic activity related to the Galactic nucleus is addressed. 126 references.