Detection of X‐Ray Emission from the Arches Cluster near the Galactic Center

The Arches cluster is an extraordinarily compact massive star cluster with acore radius of about 10$''$ ($\sim$0.4 pc) and consisting of more than 150 Ostar candidates with initial stellar masses greater than 20~M$_\odot$ nearG0.12-0.02. X-ray observations of the radio Arc near the Galactic center atl$\sim0.2^0$ which contains the Arches cluster have been carried out with theAdvanced CCD Imaging Spectrometer (ACIS) on board Chandra X-ray Observatory. Wereport the detection of two X-ray sources from the Arches cluster embeddedwithin a bath of diffuse X-ray emission extending beyond the edge of thecluster to at least 90$''\times60''$ (3.6 pc $\times$ 2.4 pc). The brightestcomponent of the X-ray emission coincides with the core of the cluster and canbe fitted with two-temperature thermal spectrum with a soft and hard componentof 0.8 and 6.4 keV, respectively. The core of the cluster coincides withseveral ionized stellar wind sources that have previously been detected atradio wavelengths, suggesting that the X-ray emission from the core arises fromstellar wind sources. The diffuse emission beyond the boundary of the clusteris discussed in the context of combined shocked stellar winds escaping from thecluster. We argue that the expelled gas from young clusters such as the Archescluster may be responsible for the hot and extended X-ray emitting gas detectedthroughout the inner degree of the Galactic center.Comment: 22 pages with 7 figures and one table, ApJ (in press