Open AccessThe K α complex of He‐like iron with dielectronic satellites
Author(s) -
Oelgoetz Justin,
Pradhan Anil K.
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04980.x
Subject(s) - physics , ionization , spectral line , plasma , atomic physics , accretion (finance) , astrophysics , line (geometry) , resonance (particle physics) , spectroscopy , absorption (acoustics) , absorption spectroscopy , ion , astronomy , nuclear physics , optics , quantum mechanics , geometry , mathematics
It is shown that the dielectronic satellites (DES) dominate X‐ray spectral formation in the 6.7‐keV K α complex of Fe xxv at temperatures below that of maximum abundance in collisional ionization equilibrium T m . Owing to their extreme temperature sensitivity, the DES are excellent spectral diagnostics for in photoionized, collisional or hybrid plasmas; whereas the forbidden, intercombination and resonance lines of Fe xxv are not. A diagnostic line ratio GD ( T ) is defined including the DES and the lines, with parameters from new relativistic atomic calculations. The DES absorption resonance strengths may be obtained from differential oscillator strengths, possibly to yield the column densities. The DES contribution to highly ionized Fe should be of interest for models of redward broadening of K α features, ionized accretion discs, accretion flows and K α temporal‐temperature variability in AGN.