2003/05/13 by P. Tozzi, P. Rosati, S. Ettori +4 · 3 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/376731
published as Astrophys.J. 593 (2003) 705-720 · 35 pages, 12 figures, ApJ in press
arxiv created 2003/05/13 · openalex publication_date 2003/08/11 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We present the analysis of the X-ray spectra of 18 distant clusters of galaxies with redshift 0.3 < z < 1.3. Most of them were observed with the Chandra satellite in long exposures ranging from 36 to 180 ks. For two of the z > 1 clusters, we also use deep XMM-Newton observations. Overall, these clusters probe the temperature range 3 keV ≲ kT ≲ 8 keV. Our analysis is aimed at deriving the iron abundance in the intracluster medium (ICM) out to the highest redshifts probed to date. Using a combined spectral fit of cluster subsamples in different redshift bins, we investigate the evolution of the mean ICM metallicity with cosmic epoch. We find that the mean Fe abundance at = 0.8 is Z = 0.25 Z ☉ , consistent with the local canonical metallicity value, Z ≃ 0.3 Z ☉ , within the 1 σ confidence level (c.l.). Medium- and low-temperature clusters ( kT < 5 keV) tend to have larger iron abundances than hot clusters. At redshift ~ 1.2 (four clusters at z > 1), we obtain a statistically significant detection of the Fe K line in only one cluster ( Z > 0.10 Z ☉ at the 90% c.l.). Combining all the current data sets from Chandra and XMM at z > 1, the average metallicity is measured to be = 0.21 Z ☉ (1 σ error), thus suggesting no evolution of the mean iron abundance out to z ≃ 1.2.