ULTRAVIOLET EMISSION LINES OF Si ii IN QUASARS—INVESTIGATING THE “Si ii DISASTER”

@article{Laha2016ULTRAVIOLETEL,
  title={ULTRAVIOLET EMISSION LINES OF Si ii IN QUASARS—INVESTIGATING THE “Si ii DISASTER”},
  author={Sibasish Laha and Francis P. Keenan and Gary J. Ferland and Catherine A. Ramsbottom and Kanti M. Aggarwal},
  journal={The Astrophysical Journal},
  year={2016},
  volume={825}
}
The observed line intensity ratios of the Si ii λ1263 and λ1307 multiplets to that of Si ii λ1814 in the broad-line region (BLR) of quasars are both an order of magnitude larger than the theoretical values. This was first pointed out by Baldwin et al., who termed it the “Si ii disaster,” and it has remained unresolved. We investigate the problem in the light of newly published atomic data for Si ii. Specifically, we perform BLR calculations using several different atomic data sets within the… 
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