Isolated hot stars in the Galactic center vicinity

Using near-infrared imaging and spectroscopy, we discuss the discovery of s ix emission-line sources within similar to 20 pc of Sgr A West but outside of the central parsec. The objects are coincident with stars seen in the J, H, and K' images; all have Bry (2.166 mu m) in emission, several also have He I (2.058 and 2.112/3 mu m), and some have He II (2.189 mu m) emission l ines. Comparison of the H- and K-band spectra of the newly discovered stars with recently published infrared spectral atlases of optically classified stars suggests that most of these stars are similar to massive stars in tra nsition (e.g., Ofpe/WN9, B[e], and LBV), although one is definitely a WN6 s tar. Two of the potential stars are associated with the radio emission regi ons A-D near Sgr A East, three are near or within the radio emission region s H1-H8 (nomenclature from Yusef-Zadeh & Morris), the last is near G0.10+0. 02 and is likely to be associated with the G0.12+0.02 (Arches) cluster of s tars, discussed in a previous paper. The stars are shown to be significant sources of ionization for their associated radio emission regions, with sev eral capable of completely ionizing the regions. These results provide addi tional support for the idea that these thermal radio regions, and similar s uch regions in the Galactic center, are indeed photoionized by hot young st ars.