2005年5月4日水曜日
2004年6月1日火曜日
Elemental abundances in the intracluster medium as observed with XMM-Newton
http://adsabs.harvard.edu/abs/2004A%26A...420..135T
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.
citations:
http://goo.gl/VbPdEq
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.
citations:
http://goo.gl/VbPdEq
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.
2003年10月12日日曜日
2003年2月1日土曜日
2002年11月1日金曜日
High resolution soft X-ray spectroscopy of the elliptical galaxy NGC 5044. Results from the reflection grating spectrometer on-board XMM-Newton
Published on A&A, 2003
abstract
The results from an X-ray spectroscopic study of the giant elliptical galaxy NGC 5044 in the center of a galaxy group are presented. The line dominated soft X-ray spectra (mainly Fe-L and O VIII
) from the diffuse gas are resolved for the first time in this system with the Reflection Grating Spectrometers on-board XMM-Newton and provide a strong constraint on the temperature structure. The spectra integrated over 2
(
20 kpc) in full-width can be described by a two temperature plasma model of 0.7 keV and 1.1 keV. Most of the latter component is consistent with originating from off-center regions. Compared to the isobaric cooling flow prediction, the observation shows a clear cut-off below a temperature of 
keV. Furthermore, the Fe and O abundances within the central 10-20 kpc in radius are accurately measured to be 
and 
times the solar ratios, respectively. The observed cut-off temperature of this galaxy and other central galaxies in galaxy groups and clusters are compared with the scale of the galaxy and properties of the surrounding intra-cluster medium. Based on this comparison, the origin of the lack of predicted cool emission is discussed.
abstract
The results from an X-ray spectroscopic study of the giant elliptical galaxy NGC 5044 in the center of a galaxy group are presented. The line dominated soft X-ray spectra (mainly Fe-L and O VIII
) from the diffuse gas are resolved for the first time in this system with the Reflection Grating Spectrometers on-board XMM-Newton and provide a strong constraint on the temperature structure. The spectra integrated over 2 (20 kpc) in full-width can be described by a two temperature plasma model of 0.7 keV and 1.1 keV. Most of the latter component is consistent with originating from off-center regions. Compared to the isobaric cooling flow prediction, the observation shows a clear cut-off below a temperature of keV. Furthermore, the Fe and O abundances within the central 10-20 kpc in radius are accurately measured to be and times the solar ratios, respectively. The observed cut-off temperature of this galaxy and other central galaxies in galaxy groups and clusters are compared with the scale of the galaxy and properties of the surrounding intra-cluster medium. Based on this comparison, the origin of the lack of predicted cool emission is discussed. Key words: galaxies: individual: NGC 5044 - galaxies: clusters: general - galaxies: abundances - X-rays: galaxies: clusters
2001年9月13日木曜日
XMM-Newton observations of the cluster of galaxies Abell 496
Accepted on A&A in 2001
abstract
The results from XMM-Newton observations of the relaxed cluster of galaxies Abell 496 are presented. The spatially-resolved X-ray spectra taken by the European Photon Imaging Cameras show a temperature drop and a Fe abundance increase in the intra-cluster medium (ICM) towards the cD galaxy at the cluster center. The abundances of Si and S also show a central enhancement. High resolution soft X-ray spectra obtained with the Reflection Grating Spectrometers provides a strong constraint on the temperature structure in the central cool plasma. Furthermore, the O abundance at the cluster core is accurately measured based on the O VIII
line detected with the RGS. Contrary to the Si, S, and Fe abundances, the O abundance is radially constant over the cluster.
abstract
The results from XMM-Newton observations of the relaxed cluster of galaxies Abell 496 are presented. The spatially-resolved X-ray spectra taken by the European Photon Imaging Cameras show a temperature drop and a Fe abundance increase in the intra-cluster medium (ICM) towards the cD galaxy at the cluster center. The abundances of Si and S also show a central enhancement. High resolution soft X-ray spectra obtained with the Reflection Grating Spectrometers provides a strong constraint on the temperature structure in the central cool plasma. Furthermore, the O abundance at the cluster core is accurately measured based on the O VIII
line detected with the RGS. Contrary to the Si, S, and Fe abundances, the O abundance is radially constant over the cluster. Key words: galaxies: clusters: individual: Abell 496 - galaxies: clusters: general - galaxies: abundances - X-rays: galaxies: clusters
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