Issue |
A&A
Volume 472, Number 3, September IV 2007
|
|
---|---|---|
Page(s) | 757 - 762 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:20077563 | |
Published online | 16 July 2007 |
X-ray measured metallicities of the intra-cluster medium: a good measure for the metal mass?
Institut für Astro- und Teilchenphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria e-mail: wolfgang.e.kapferer@uibk.ac.at
Received:
28
March
2007
Accepted:
10
July
2007
Aims.We investigate whether X-ray observations map heavy elements in the Intra-Cluster Medium (ICM) well and whether the X-ray observations yield good estimates for the metal mass, with respect to predictions on transport mechanisms of heavy elements from galaxies into the ICM. We further test the accuracy of simulated metallicity maps.
Methods.We extract synthetic X-ray spectra from N-body/hydrodynamic simulations including metal enrichment processes, which we then analyse with the same methods as are applied to observations. By changing the metal distribution in the simulated galaxy clusters, we investigate the dependence of the overall metallicity as a function of the metal distribution. In addition we investigate the difference of X-ray weighted metal maps produced by simulations and metal maps extracted from artificial X-ray spectra, which we calculate with SPEX2.0 and analyse with XSPEC12.0.
Results.The overall metallicity depends strongly on the
distribution of metals within the galaxy cluster. The more
inhomogeneously the metals are distributed within the cluster, the
less accurate is the metallicity as a measure for the true metal
mass. The true metal mass is generally underestimated by X-ray
observations. The difference between the X-ray weighted metal maps
and the metal maps from synthetic X-ray spectra is on average less
than 7% in the temperature regime above T > 3 107 K, i.e.
X-ray weighted metal maps can be well used for comparison with
observed metal maps. Extracting the metal mass in the central parts
(r < 500 kpc) of galaxy clusters with X-ray observations results in
metal mass underestimates up to a factor of three.
Key words: hydrodynamics / methods: numerical / galaxies: intergalactic medium
© ESO, 2007
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.