Diffuse X-rays from the Arches and Quintuplet Clusters

The origin and initial mass function of young stellar clusters near the Galactic center are still poorly understood. Two of the more prominent ones, the Arches and Quintuplet clusters, may have formed from a shock-induced burst of star formation, given their similar age and proximity to each other. Their unusual mass distribution, however, may be evidence of a contributing role played by other factors, such as stellar capture from regions outside the clusters themselves. Diffuse X-ray emission from these sources provides us with a valuable, albeit indirect, measure of the stellar mass-loss rate from their constituents. Using recent data acquired with Chandra, we can study the nature and properties of the outflow to not only probe the pertinent physical conditions, such as high metallicity, the magnetic field, and so forth, but also to better constrain the stellar distribution within the clusters, in order to identify their formative history. In this paper, we present a set of three-dimensional smoothed particle hydrodynamics simulations of the wind-wind interactions in both the Arches and Quintuplet clusters. We are guided primarily by the currently known properties of the constituent stars, though we vary the mass-loss rates in order to ascertain the dependence of the measured X-ray flux on the assumed stellar characteristics. Our results are compared with the latest observations of the Arches cluster. Our analysis of the Quintuplet cluster may be used as a basis for comparison with future X-ray observations of this source. Subject headings: galaxies: clusters: individual (Arches, Quintuplet)—Galaxy: center—radiation mechanisms: thermal—shock waves—stars: winds—X-rays: diffuse Department of Physics, The University of Arizona, 1118 E 4th St, Tucson, AZ 85721 Theoretical Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 Steward Observatory, The University of Arizona, 933 N Cherry Ave, Tucson, AZ 85721 Sir Thomas Lyle Fellow and Miegunyah Fellow. Department of Astronomy, University of Massachusetts, 710 N Pleasant St, Amherst, MA 01003