SIMBAD references

2013ApJS..208...10D - Astrophys. J., Suppl. Ser., 208, 10 (2013/September-0)

New strong-line abundance diagnostics for H II regions: effects of κ-distributed electron energies and new atomic data.

DOPITA M.A., SUTHERLAND R.S., NICHOLLS D.C., KEWLEY L.J. and VOGT F.P.A.

Abstract (from CDS):

Recently, Nicholls et al., inspired by in situ observations of solar system astrophysical plasmas, suggested that the electrons in H II regions are characterized by a κ-distribution of energies rather than a simple Maxwell-Boltzmann distribution. Here, we have collected together new atomic data within a modified photoionization code to explore the effects of both the new atomic data and the κ-distribution on the strong-line techniques used to determine chemical abundances in H II regions. By comparing the recombination temperatures (Trec) with the forbidden line temperatures (TFL), we conclude that κ ∼ 20. While representing only a mild deviation from equilibrium, this result is sufficient to strongly influence abundances determined using methods that depend on measurements of the electron temperature from forbidden lines. We present a number of new emission line ratio diagnostics that cleanly separate the two parameters determining the optical spectrum of H II regions–the ionization parameter q or {U} and the chemical abundance, 12+log(O/H). An automated code to extract these parameters is presented. Using the homogeneous data set from van Zee et al., we find self-consistent results between all of these different diagnostics. The systematic errors between different line ratio diagnostics are much smaller than those found in the earlier strong-line work. Overall, the effect of the κ-distribution on the strong-line abundances derived solely on the basis of theoretical models is rather small.

Abstract Copyright:

Journal keyword(s): atomic data - atomic processes - H II regions - ISM: abundances - plasmas

VizieR on-line data: <Available at CDS (J/ApJS/208/10): table1.dat table4.dat table5.dat table6.dat>

Status at CDS:  

Simbad objects: 17

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2020.06.03-21:09:04

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