On the Apparent Narrowing of Radio Recombination Lines at High Principal Quantum Numbers

  title={On the Apparent Narrowing of Radio Recombination Lines at High Principal Quantum Numbers},
  author={J. Alexander and Sergei Gulyaev},
  journal={The Astrophysical Journal},
We critically analyze Bell et al.’s findings on “anomalous” widths of high-order hydrogen radio recombination lines in the Orion Nebula at 6 GHz. We review their method of modified frequency switching and show that the way this method is used for large Δn is not optimal and can lead to misinterpretation of measured spectral line parameters. Using a model of the Orion Nebula, conventional broadening theory, and Monte Carlo simulation, we determine a transition zone n = 224 ,..., 241 (Δn = 11… 

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