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in creator/contributor: "Kaastra, J. S."  
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New calculations of Fe spectra in high-temperature plasmas

Description: Spectroscopic data acquired during the ASCA performance verification phase have revealed a discrepancy between measured line flux ratios and the predictions of standard plasma emission codes. In plasmas for which coronal ionization equilibrium should apply, flux ratios of 4--2 and 3--2 line complexes in highly-ionized Fe are observed to be significantly lower than predicted, thus compromising the quality of spectral fits. We have recalculated Fe L-shell spectra using the HULLAC atomic physics p… more
Date: March 30, 1994
Creator: Liedahl, D. A.; Osterheld, A. L.; Mewe, R. & Kaastra, J. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The O VII X-Ray Forest Toward Markarian 421: Consistency between XMM-Newton and Chandra

Description: Recently the first detections of highly ionized gas associated with two Warm-Hot Intergalactic Medium (WHIM) filaments have been reported. The evidence is based on X-ray absorption lines due to O VII and other ions observed by Chandra towards the bright blazar Mrk 421. We investigate the robustness of this detection by a re-analysis of the original Chandra LETGS spectra, the analysis of a large set of XMM-Newton RGS spectra of Mrk 421, and additional Chandra observations. We address the reliabi… more
Date: April 28, 2006
Creator: Kaastra, J. S.; Werner, N.; den Herder, J. W. A.; /SRON, Utrecht; Paerels, F. B. S.; /Columbia U., Astron. Astrophys. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

XMM-Newton Spectroscopy of the Cluster of Galaxies 2a 0335+096

Description: We present here the results of a deep (130 ks) XMM-Newton observation of the cluster of galaxies 2A 0335+096. The deep exposure allows us to study in detail its temperature structure and its elemental abundances. We fit three different thermal models and find that the multi-temperature wdem model fits our data best. We find that the abundance structure of the cluster is consistent with a scenario where the relative number of Type Ia supernovae contributing to the enrichment of the intra-cluster… more
Date: January 17, 2006
Creator: Werner, Norbert; /SRON, Utrecht; de Plaa, J.; /SRON, Utrecht /Utrecht U.; Kaastra, J.S.; /SRON, Utrecht et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Chemical Evolution in Sersic 159-03 Observed with Xmm-Newton

Description: Using a new long X-ray observation of the cluster of galaxies Sersic 159-03 with XMM-Newton, we derive radial temperature and abundance profiles using single- and multi-temperature models. The fits to the EPIC and RGS spectra prefer multi-temperature models especially in the core. The radial profiles of oxygen and iron measured with EPIC/RGS and the line profiles in RGS suggest that there is a dip in the O/Fe ratio in the centre of the cluster compared to its immediate surroundings. A possible … more
Date: March 10, 2006
Creator: de Plaa, Jelle; Werner, N.; Bykov, A.M.; Kaastra, J.S.; Mendez, M.; Vink, J. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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