H-, He-like recombination spectra III. n-changing collisions in highly-excited Rydberg states and their impact on the radio, IR and optical recombination lines

F. Guzmán, M. Chatzikos, P. A. M. van Hoof, Dana S. Balser, M. Dehghanian, N. R. Badnell, G.J. Ferland

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

At intermediate to high densities, electron (de-)excitation collisions are the dominant process for populating or depopulating high Rydberg states. In particular, the accurate knowledge of the energy changing (n-changing) collisional rates is determinant for predicting the radio recombination spectra of gaseous nebula. The different data sets present in the literature come either from impact parameter calculations or semi-empirical fits and the rate coefficients agree within a factor of 2. We show in this paper that these uncertainties cause errors lower than 5 per cent in the emission of radio recombination lines of most ionized plasmas of typical nebulae. However, in special circumstances where the transitions between Rydberg levels are amplified by maser effects, the errors can increase up to 20 per cent. We present simulations of the optical depth and Hnα line emission of active galactic nuclei broad-line regions and the Orion Nebula Blister to showcase our findings.

LanguageEnglish
Pages1003–1018
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Volume486
Issue number1
Early online date27 Mar 2019
DOIs
Publication statusPublished - 1 Jun 2019

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nebulae
recombination
collision
radio
Orion nebula
blisters
collisions
masers
determinants
active galactic nuclei
optical thickness
electron density
optical depth
plasma
causes
coefficients
excitation
simulation
energy
rate

Keywords

  • recombination spectra
  • Rydberg states
  • electron collisions
  • radio recombination lines

Cite this

Guzmán, F. ; Chatzikos, M. ; van Hoof, P. A. M. ; Balser, Dana S. ; Dehghanian, M. ; Badnell, N. R. ; Ferland, G.J. / H-, He-like recombination spectra III. n-changing collisions in highly-excited Rydberg states and their impact on the radio, IR and optical recombination lines. In: Monthly Notices of the Royal Astronomical Society. 2019 ; Vol. 486, No. 1. pp. 1003–1018.
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H-, He-like recombination spectra III. n-changing collisions in highly-excited Rydberg states and their impact on the radio, IR and optical recombination lines. / Guzmán, F.; Chatzikos, M. ; van Hoof, P. A. M.; Balser, Dana S.; Dehghanian, M.; Badnell, N. R.; Ferland, G.J.

In: Monthly Notices of the Royal Astronomical Society, Vol. 486, No. 1, 01.06.2019, p. 1003–1018.

Research output: Contribution to journalArticle

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