THE ARCHES CLUSTER: PROBING THE INTERACTION BETWEEN MASSIVE STARS AND THE ISM IN THE GALACTIC CENTER

this director.s discretionary time proposal will use midinfrared atomic finestructure lines to probe the excitation conditions of the ism in the vicinity of the recentlydiscovered arches cluster, g0.12+0.02 (cotera et al. 1996; see also nagata et al. 1993, 1995, 1996). the arches cluster is perhaps the most powerful cluster in the galactic center, and new imaging with keck (serabyn et al. 1998) suggests that there are more massive o stars in this cluster than in any known cluster in the entire galactic disk. as this massive young star cluster lies in a region with an estimated 30 magnitudes of visual extinction, midinfrared spectroscopy with iso is uniquely poised to probe its effects on the interstellar medium in the extreme environment of the galactic center. a nearinfrared spectroscopic study of the arches cluster (cotera et al. 1996) describes the detection of 13 emissionline stars. the keck imaging study suggests there are virgul100 main sequence o stars in this young cluster, including a significant population of the youngest, most massive o stars known (serabyn et al. 1998). a detailed examination of the excitation produced by these massive stars, using sws spectroscopy, will make an important contribution to understanding the interaction of massive stars and the ism in different star formation environments. a study of the excitation of the arches cluster has important implications for the interpretation of similar diagnostics in the more distant starformation environments of starburst nuclei, where the stellar population cannot be directly observed. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]