Metals in the intracluster medium

Abstract

Supernovae contributions to metals in intra-cluster medium observed with Suzaku AIP Conf.On the halo neutron star origin of the gamma-ray bursts: Origin of the halo neutron stars and metal enrichment of the intracluster medium AIP Conf.Abstract. We derived radial abundance profiles of O, Mg, Si, S and Fe in the intracluster medium (ICM) of several clusters and groups of galaxies up to about 0.3 r 180 with Suzaku and those of Fe in 28 nearby brightest clusters of galaxies up to 0.3-0.5 r 180 with XMM. Within 0.05 r 180 , Fe abundance scatters from 0.5 to 1 solar. The scatter may be caused by a difference in recent metal supplies with supernovae Ia and stellar mass loss from cD galaxies. In these regions and also in ISM in giant elliptical galaxies, the abundance patterns of O, Mg, Si, S and Fe are close to the solar ratio adopting the new solar abundance defined by Lodders [1]. At 0.1-0.5 r 180 , relaxed clusters with a cD galaxy at their X-ray peak have flat Fe abundance profiles at 0.4-0.5 solar, with a small scatter. In these clusters, the ratio of Fe mass in the ICM to the light from galaxies have similar profiles, and increases toward outer regions. In addition, several systems show a hint of enhancement of O/Fe and Mg/Fe ratios. These results indicate that the metal-enrichment process in these clusters has been universal, and a significant amount of Fe is synthesized at a very early stage in cluster formation. Scatter in the metal-mass-to-light ratios and similarity in the abundances in the ICM of groups and clusters of galaxies also indicate early metal synthesis.

Metal-Mass-to-Light Ratios of the Perseus Cluster Out to the Virial Radius

“…They discussed the initial enrichment by SNcc in the early phase in cluster evolution and mixing of these metals. The O/Fe and Mg/Fe ratios within the cool core of the Perseus cluster are about unity in solar units (Matsushita & Tamura 2011) and agrees with the O/Fe ratio in the cool core of the Hydra A cluster (Simionescu et al 2009). The metals already synthesized in the protocluster phase can dominate those in the central regions of these two clusters.…”

“…Here, we used the weighted average of the E and NW results of Suzaku. 2007;de Grandi & Molendi 2009;Simionescu et al 2009;Matsushita et al 2012). Since Si and Fe were synthesized by both SN Ia and SNcc, the contribution of the two types of SN strongly depends on the adopted nucleosynthesis model of SN Ia.…”

“…With ASCA observations, the derived IMLR within a radius where the ICM density falls below 3 ×10 −4 cm −3 is nearly constant in rich clusters and decreases toward poorer systems (Makishima et al 2001). With Suzaku, Chandra, and XMM satellites, the IMLR of several medium-sized clusters and groups of galaxies was measured out to 0.2r 180 -0.5r 180 (Matsushita et al 2007a;Komiyama et al 2009;Sato et al 2007Sato et al , 2008Sato et al , 2009aSato et al ,b, 2010Rasmussen & Ponman 2009;Sakuma et al 2011) and that of the Coma cluster was derived out to 0.5r 180 (Matsushita et al 2012). Suzaku first measured the Fe abundance of the ICM beyond 0.5r 180 (Fujita et al 2008;Simionescu et al 2011).…”

“…However, excluding cool-core regions, the error bars in the Si/Fe ratio of hotter clusters are very large (Tamura et al 2004). Matsushita et al (2012) derived the Si/Fe ratio in the ICM of the Coma cluster from the flux ratios of the Lyα line of H-like Si and the Kα line of He-like Fe. The temperature dependence of the line ratio above several keV is relatively small and limits the systematic uncertainty in the derived abundance ra-tio.…”