{
  "id": "1001.3627",
  "version": "v1",
  "published": "2010-01-20T15:51:33.000Z",
  "updated": "2010-01-20T15:51:33.000Z",
  "title": "Emission lines of Fe XI in the 257--407 A wavelength region observed in solar spectra from EIS/Hinode and SERTS",
  "authors": [
    "F. P. Keenan",
    "R. O. Milligan",
    "D. B. Jess",
    "K. M. Aggarwal",
    "M. Mathioudakis",
    "R. J. Thomas",
    "J. W. Brosius",
    "J. M. Davila"
  ],
  "comment": "9 pages, 5 figures, 13 tables; MNRAS in press",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "Theoretical emission-line ratios involving Fe XI transitions in the 257-407 A wavelength range are derived using fully relativistic calculations of radiative rates and electron impact excitation cross sections. These are subsequently compared with both long wavelength channel Extreme-Ultraviolet Imaging Spectrometer (EIS) spectra from the Hinode satellite (covering 245-291 A), and first-order observations (235-449 A) obtained by the Solar Extreme-ultraviolet Research Telescope and Spectrograph (SERTS). The 266.39, 266.60 and 276.36 A lines of Fe XI are detected in two EIS spectra, confirming earlier identifications of these features, and 276.36 A is found to provide an electron density diagnostic when ratioed against the 257.55 A transition. Agreement between theory and observation is found to be generally good for the SERTS data sets, with discrepancies normally being due to known line blends, while the 257.55 A feature is detected for the first time in SERTS spectra. The most useful Fe XI electron density diagnostic is found to be the 308.54/352.67 intensity ratio, which varies by a factor of 8.4 between N_e = 10^8 and 10^11 cm^-3, while showing little temperature sensitivity. However, the 349.04/352.67 ratio potentially provides a superior diagnostic, as it involves lines which are closer in wavelength, and varies by a factor of 14.7 between N_e = 10^8 and 10^11 cm^-3. Unfortunately, the 349.04 A line is relatively weak, and also blended with the second-order Fe X 174.52 A feature, unless the first-order instrument response is enhanced.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2010-01-20T15:51:33.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "solar spectra",
      "impact excitation cross sections",
      "wavelength region",
      "fe xi electron density",
      "emission lines"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1111/j.1365-2966.2010.16389.x",
      "journal": "Monthly Notices of the Royal Astronomical Society",
      "year": 2010,
      "month": "May",
      "volume": 404,
      "number": 3,
      "pages": 1617
    },
    "note": {
      "typesetting": "TeX",
      "pages": 9,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 843313,
      "adsabs": "2010MNRAS.404.1617K"
    }
  }
}