{
  "id": "2007.16106",
  "version": "v1",
  "published": "2020-07-31T14:38:09.000Z",
  "updated": "2020-07-31T14:38:09.000Z",
  "title": "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",
  "authors": [
    "P. Chakraborty",
    "M. Chatzikos",
    "F. Guzmán",
    "Y. Su",
    "G. J. Ferland"
  ],
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "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.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-07-31T14:38:09.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "column density",
      "x-ray spectroscopy",
      "fe xxv",
      "microcalorimeter era",
      "he-like iron"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}