THE DISCOVERY OF HOT STARS NEAR THE GALACTIC-CENTER THERMAL RADIO FILAMENTS

We report the discovery of a highly unusual cluster of stars at G0.121 +0.017 near the Arched (thermal) Filaments, similar to 10' northeast o f the Galactic center. H (1.65 mu m) and K' (2.1 mu m) images are used to estimate a distance to the cluster consistent with a Galactic cent er location. K'-band spectroscopy reveals that the cluster contains 13 stars with Br gamma (2.166 mu m) emission: 12 of these stars also hav e He I (2.112/3 mu m) emission, and two show fainter He II (2.189 mu m ) emission. Based on a spectral comparison with optically classified s tars, we suggest the new emission stars are late WN stars. If the clas sification is correct, the cluster contains similar to 14% of all know n Galactic WN stars. Observations of emission-line stars near G0.15-0. 05, the ''Pistol,'' are also presented. There are four stars near the Pistol which contain emission lines. Three of these stars differ spect roscopically from the stars in the new cluster; one has a spectrum tha t is similar to the new cluster stars. Together with the cluster stars , these newly discovered hot young stars provide evidence for recent s tar formation and the stellar ionization of the thermal radio emission regions in the vicinity of the Galactic center.