Excitation of the [Fe III] bubble surrounding the galactic center mini-cavity

We present spectroscopy and 1″ narrow-band imaging of near-infrared line emission in the central 0.3 pc of the Galaxy. The mini-cavity region 3″.5 southwest of the compact radio source Sgr A * is a source of bright 2.2178 μm line emission that is now unambiguously identified as [Fe III] by detection of three additional [Fe III] lines. The derived fractional abundances of [Fe]/[H] ≥2.5×10 −5 and [Fe ++ ]/[Fe + ] ≃1 together with the observed spatial distributions and line profiles of [Fe III] and H I Brγ suggest the following model of the mini-cavity region