X-ray spectroscopy in the microcalorimeter era II: A new Diagnostic on Column Density from the Case A to B Transition in H- and He-like Iron. (arXiv:2007.16106v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Chakraborty_P/0/1/0/all/0/1">P. Chakraborty</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chatzikos_M/0/1/0/all/0/1">M. Chatzikos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guzman_F/0/1/0/all/0/1">F. Guzmán</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Su_Y/0/1/0/all/0/1">Y. Su</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ferland_G/0/1/0/all/0/1">G. J. Ferland</a>
The Soft X-ray Spectrometer (SXS) on board textit{Hitomi}, with the
unprecedented resolving power of R$sim$1250, allowed the detection of members
of the Fe XXV ka complex emission spectra from the center of the Perseus
Cluster. In this paper, we introduce a novel method of measuring the column
density using the optically thin (Case A) to optically thick (Case B)
transition for one- and two-electron systems. We compare the Fe XXV K$alpha$
line ratios computed with CLOUDY with that from the textit{Hitomi}
observations in the outer region of the Perseus core using collision strengths
from different atomic datasets, and obtain good agreement. We also show the
effect of turbulence on Fe XXV K$alpha$ line ratios and interplay between
column density and metallicity. Besides, we discuss the atomic number
dependence of transition probabilities for allowed and non-allowed transitions,
which causes the highly charged He-like systems, such as Fe XXV, to behave
fundamentally differently from He I.
The Soft X-ray Spectrometer (SXS) on board textit{Hitomi}, with the
unprecedented resolving power of R$sim$1250, allowed the detection of members
of the Fe XXV ka complex emission spectra from the center of the Perseus
Cluster. In this paper, we introduce a novel method of measuring the column
density using the optically thin (Case A) to optically thick (Case B)
transition for one- and two-electron systems. We compare the Fe XXV K$alpha$
line ratios computed with CLOUDY with that from the textit{Hitomi}
observations in the outer region of the Perseus core using collision strengths
from different atomic datasets, and obtain good agreement. We also show the
effect of turbulence on Fe XXV K$alpha$ line ratios and interplay between
column density and metallicity. Besides, we discuss the atomic number
dependence of transition probabilities for allowed and non-allowed transitions,
which causes the highly charged He-like systems, such as Fe XXV, to behave
fundamentally differently from He I.
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