Deep Chandra Observations of the Arches and Quintuplet Clusters at the Galactic Center

We present a deep Chandra ACIS-I observation of the Arches and Quintuplet clusters at the Galactic Center. We detect several bright point-like sources that are clearly associated with the clusters. Some of the sources are positionally coincident with known radio sources with strong stellar winds. The sources have similar X-ray spectra, which are dominantly thermal and show an unusually strong 6.7 keV emission line, indicating that they are most likely the colliding wind close binaries of very massive stars. The spectra of the diffuse X-ray emission are significantly flatter than that of point-like sources. The luminosity, spectrum, and spatial distribution of the diffuse emission suggest that it arises primarily in cluster winds. Away from the Arches cluster, an enhanced diffuse X-ray feature shows a strong 6.4-keV emission line, but is not associated with any dense molecular cloud. The nature of this feature is still unknown.