The iron K line analysis of clusters of galaxies observed with ASCA

F. Akimoto^1,2, A. Furuzawa¹, Y. Tawara¹, K. Yamashita¹

1: Department of Physics, Nagoya University
2: Research Center for Advanced Energy Conversion, Nagoya University

Abstract

ASCA observations of some nearby cool clusters of galaxies make it clear that they have larger iron K beta line intensities than ones expected from plasma temperatures and iron K alpha line intensities. For each hot cluster of galaxies, because line intensity is small, this phenomenon is not clear. Therefore, the 150 clusters of galaxies are classified within 5 groups according to plasma temperature and all spectra are summed for each group, after correction of redshift. As the results, these spectra have iron line intensity affected by the effect of resonance scattering (optical depth is about 2). Moreover, the summed SIS spectra revealed the He-like iron K beta line and H-like iron K beta line. The interpretation of these line intensities needs the effects of the resonance scattering. This means the iron abundances driven from He-like iron K alpha are underestimated at the center of clusters of galaxies, if this effect is not corrected. The correction of this effect is inclined to strengthen the concentration of abundance at the center of galaxy clusters and to make the variety of abundance of each galaxy cluster large.