An iterative technique for solving equations of statistical equilibrium |
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| Authors: | LB Lucy |
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| Institution: | Astrophysics Group, Blackett Laboratory, Imperial College of Science, Technology and Medicine, Prince Consort Road, London SW7 2BW |
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| Abstract: | Superlevel partitioning is combined with a simple relaxation procedure to construct an iterative technique for solving equations of statistical equilibrium. In treating an N -level model atom, the technique avoids the N 3 scaling in computer time for direct solutions with standard linear equation routines and also does not fail at large N due to the accumulation of round-off errors. As a consequence, the technique allows detailed model atoms with N ?103 , such as those required for iron peak elements, to be incorporated into diagnostic codes for analysing astronomical spectra. Tests are reported for a 394-level Fe ii ion and a 1266-level Ni i – iv atom. |
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| Keywords: | line: formation radiative transfer methods: numerical stars: atmospheres |
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