On the Iron content in rich nearby Clusters of Galaxies.pdf

a r X i v : a s t r o - p h / 0 3 1 0 8 2 8 v 1 2 9 O c t 2 0 0 3 Astronomy Astrophysics manuscript no. degrandi˙astroph February 2, 2008 (DOI: will be inserted by hand later) On the Iron content in rich nearby Clusters of Galaxies S. De Grandi 1 , S. Ettori 2 , M. Longhetti 1 and S. Molendi 3 1 INAF - Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate (LC) e-mail: degrandi@mi.astro.it; marcella@mi.astro.it 2 ESO - Headquarter, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Mu?nchen e-mail: settori@eso.org 3 Istituto di Astrofisica Spaziale e Fisica Cosmica (CNR) via Bassini 15, I-20133 Milano e-mail: silvano@mi.iasf.cnr.it Accepted for publication in AA Abstract. In this paper we study the iron content of a sample of 22 nearby hot clusters observed with BeppoSAX. We find that the global iron mass of clusters is tightly related to the cluster luminosity and that the relatively loose correlation between the iron mass and the cluster temperature follows from the combination of the iron mass vs. luminosity and luminosity vs. temperature correlations. The iron mass is found to scale linearly with the intracluster gas mass, implying that the global iron abundance in clusters is roughly constant. This result suggests that enrichment mechanisms operate at a similar rate in all clusters. By employing population synthesis and chemical enrichment models, we show that the iron mass associated to the abundance excess which is always found in the centre of cool core clusters can be entirely produced by the brightest cluster galaxy (BCG), which is always found at the centre of cool core clusters. The iron mass associated to the excess, the optical magnitude of the BCG and the temperature of the cluster are found to correlate with one another suggesting a link between the properties of the BCG and the hosting cluster. These observational facts lends strength to current formation theories which envisage a strong connection between the formation of the giant