Astrophys. J., 631, 197-207 (2005/September-3)
Chandra observation of the cluster of galaxies MS 0839.9+2938 at z = 0.194: the central excess iron and type Ia supernova enrichment.
WANG Y., XU H., ZHANG Z., XU Y., WU X.-P., XUE S.-J. and LI Z.
Abstract (from CDS):
We present the Chandra study of the intermediate-redshift (z=0.194) cluster of galaxies MS 0839.9+2938. By performing both projected and deprojected spectral analyses, we find that the gas temperature is approximately constant at about 4 keV within 130-444 h–170kpc. In the inner regions, the gas temperature decreases toward the center, reaching ≲3 keV in the central 37 h–170kpc. This implies that the lower and upper limits of the mass deposit rate are 9-34 and 96-126 M☉/yr, respectively, within 74 h–170kpc, where the gas is significantly colder. Along with the temperature drop, we detect a significant inward iron abundance increase from about 0.4 Z☉in the outer regions to ≃1 Z☉within the central 37 h–170kpc. Thus, MS 0839.9+2938 is the cluster showing the most significant central iron excess at z≳0.2. We argue that most of the excess iron should have been contributed by SNe Ia. Using the observed SN Ia rate and stellar mass loss rate, we estimate that the time needed to enrich the central region with excess iron is 6.4-7.9 Gyr, which is similar to those found for nearby clusters. Coinciding with the optical extension of the cD galaxy (up to about 30 h–170kpc), the observed X-ray surface brightness profile exhibits an excess beyond the distribution expected by either the β model or the Navarro-Frenk-White (NFW) model and can be well fitted with an empirical two-β model that leads to a relatively flatter mass profile in the innermost region.
Galaxies: Clusters: Individual: Alphanumeric: MS 0839.9+2938 - Galaxies: Evolution - Galaxies: Intergalactic Medium - X-Rays: Galaxies: Clusters
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