Uncertainties in Atomic Data and Their Propagation Through Spectral Models. I

M.A. Bautista (1), V. Fivet (1,2), P. Quinet (2), J. Dunn (3), T.R. Gull (4), T.R. Kallman (5), C. Mendoza (6) ((1) Department of Physics, Western Michigan University, Kalamazoo, MI 49008, USA; (2) Astrophysique et Spectroscopie, Université de Mons UMONS, 7000 Mons, Belgium; (3)  Physical Science Department, Georgia Perimeter College, Dunwoody, GA 30338, USA; (4) NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA;
(5) Code 662, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA;
(6) Centro de Física, Instituto Venezolano de Investigaciones Científicas (IVIC), PO Box
20632, Caracas 1020A, Venezuela)

We present a method for computing uncertainties in spectral models, i.e. level populations, line emissivities, and emission line ratios, based upon the propagation of uncertainties originating from atomic data. We provide analytic expressions, in the form of linear sets of algebraic equations, for the coupled uncertainties among all levels. These equations can be solved efficiently for any set of physical conditions and uncertainties in the atomic data. We illustrate our method applied to spectral models of O III and Fe II and discuss the impact of the uncertainties on atomic systems under different physical conditions. As to intrinsic uncertainties in theoretical atomic data, we propose that these uncertainties can be estimated from the dispersion in the results from various independent calculations. This technique provides excellent results for the uncertainties in A-values of forbidden transitions in [Fe II].

See complete preprint –> http://arxiv.org/abs/1301.3463

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