ラベル Peterson.J.R. の投稿を表示しています。 すべての投稿を表示
ラベル Peterson.J.R. の投稿を表示しています。 すべての投稿を表示

2004年2月27日金曜日

Elemental abundances in the intracluster medium as observed with XMM-Newton[*]

Accepted on 2004-2-27

A&A link


Abstract
XMM-Newton observations of 19 galaxy clusters are used to measure the elemental abundances and their spatial distributions in the intracluster medium. The sample mainly consists of X-ray bright and relaxed clusters with a cD galaxy. Along with detailed Si, S and Fe radial abundance distributions within 300-700 kpc in radius, the O abundances are accurately derived in the central region of the clusters. The Fe abundance maxima towards the cluster center, possibly due to the metals from the cD galaxy, are spatially resolved. The Si and S abundances also exhibit central increases in general, resulting in uniform Fe-Si-S ratios within the cluster. In contrast, the O abundances are in general uniform over the cluster. The mean O to Fe ratio within the cluster core is sub-solar, while that of the cluster scale is larger than the solar ratio. These measurements indicate that most of the Fe-Si-S and O in the intracluster medium have different origins, presumably in supernovae Ia and II, respectively. The obtained Fe and O mass are also used to discuss the past star formation history in clusters.

2000年10月1日日曜日

X-ray spectroscopy of the cluster of galaxies Abell 1795 with XMM-Newton

Accepted on A&A in 2001.

Abstract
The initial results from XMM-Newton observations of the rich cluster of galaxies Abell 1795 are presented. The spatially-resolved X-ray spectra taken by the European Photon Imaging Cameras (EPIC) show a temperature drop at a radius of $\sim$200 kpc from the cluster center, indicating that the ICM is cooling. Both the EPIC and the Reflection Grating Spectrometers (RGS) spectra extracted from the cluster center can be described by an isothermal model with a temperature of $\sim$4 keV. The volume emission measure of any cool component (VIII Lyman $\alpha$ line was detected with the RGS from the cluster core. The O abundance and its ratio to Fe at the cluster center is 0.2-0.5 and 0.5-1.5 times the solar value, respectively.

http://adsabs.harvard.edu/abs/2001A%26A...365L..87T

citation papers
http://goo.gl/4iwcJC