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Session 7 - Gas and Dust in the ISM.
Display session, Monday, June 10
Great Hall,
The ionization structure and emission spectra of Fe ions in gaseous nebulae are studied. The theoretical models are based on extensive atomic calculations for the low ionization stages of Fe: I,II,III,IV, and V, by the Ohio State atomic-astrophysics group. The theoretical models include (i) new atomic data: photoionization cross sections, total e-ion recombination rates, collision strengths, and transition probabilities, (ii) collisional-radiative excitation of Fe ions; (iii) study of the physical structure of nebula including density and temperature fluctuations and kinematic effects. Our results differ considerably from those obtained in previous work, mainly owing to the new atomic data. Results will be presented for the ionization structure of Fe I-IV, as well as for the emission spectra of Fe ions in gaseous nebulae. These calculations should also allow for a more accurate estimation of the Fe abundance in astronomical objects in general.
