A masing [Fe XI] line

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3 Scopus citations


I draw attention to a maser which occurs within the ground term of Fe+10. In many photoionized environments, infrared fine-structure lines and the [O I] λ6300 line become optically thick but maser amplification of ionic fine-structure lines is unusual. During the course of development of a code designed to simulate gas under radiative-collisional equilibrium, the radiative transfer of roughly 500 ionic/atomic emission lines has been treated using escape probabilities. Nearly all forbidden lines can become optically thick under extreme conditions, but the 3Pj = 1, 0 [Fe xi] 6.08 μm transition is the only line which routinely mases and can reach optical depths smaller than -5. Maser effects can alter the intensity ratio of the infrared line relative to 3Pj = 2, l λ7892 by half an order of magnitude under certain conditions. A model of the coronal line region of Nova Cyg 1975 is presented, which illustrates the effects of this maser.

Original languageEnglish
Pages (from-to)49-52
Number of pages4
JournalAstrophysical Journal, Supplement Series
Issue number1
StatePublished - 1993


  • Atomic processes
  • Galaxies: Seyfert
  • Galaxies: active
  • Infrared: galaxies
  • Masers

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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