J/ApJS/208/10 Effects of a κ-distribution in HII regions (Dopita+, 2013)
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., Vogt F.P.A.
<Astrophys. J. Suppl. Ser., 208, 10 (2013)>
=2013ApJS..208...10D 2013ApJS..208...10D
ADC_Keywords: Atomic physics ; H II regions ; Abundances
Keywords: atomic data, atomic processes, H II regions, ISM: abundances, plasmas
Abstract:
Recently, Nicholls et al. (2012ApJ...752..148N 2012ApJ...752..148N), 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 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. 1998,
Cat. J/AJ/116/2805, 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.
Description:
We have modified the MAPPINGS code (Sutherland & Dopita
1993ApJS...88..253S 1993ApJS...88..253S; Allen et al. 2008ApJS..178...20A 2008ApJS..178...20A) to incorporate
new non-thermal (κ) electron energy excitation (Nicholls et al.
2012ApJ...752..148N 2012ApJ...752..148N, 2013ApJS..207...21N 2013ApJS..207...21N) and to bring the atomic data
and the Maxwell-averaged collision strengths up to date. The number of
ionic species treated as full non-local thermal equilibrium
multi-level ions has increased from 37 to 43. The multi-level atoms
are modeled using anywhere from three to nine levels depending on the
ionic configuration.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 80 30 Literature sources used for collision strength data
table4.dat 111 324 The "blue" line fluxes given by the MAPPINGS 4
models relative to FHβ=1.0
table5.dat 111 324 The "red" line fluxes given by the MAPPINGS 4
models relative to FHβ=1.0
table6.dat 60 324 The recombination and forbidden line temperatures
of the MAPPINGS 4 models
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See also:
J/A+A/528/A69 : Li-like iso-electronic sequence (Liang+, 2011)
J/ApJS/188/32 : Breit-Pauli transition probabilities for SII (Tayal+, 2010)
J/A+A/486/629 : Effective collision strengths for C II (Tayal, 2008)
J/ApJS/163/207 : Oscillator and collision strengths in NI (Tayal+, 2006)
J/AJ/116/2805 : H II regions in spiral galaxies (Van Zee+, 1998)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Ion Ion identification
9- 30 A22 --- Aut Author's name(s)
33- 51 A19 --- BibCode Bibcode
54- 80 A27 --- Comm VizieR catalog reference or comment
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 F4.2 Sun Z [0.05/5] Model metallicity (relative to Sun)
6- 7 I2 --- kappa [10/50]? Model κ value
8 A1 --- f_kappa [i] i: infinite (kappa is blank)
10- 13 F4.2 [m/s] logq [6.5/8.5] Model ionization parameter (G1)
15- 20 F6.4 --- O2-3727 The [O II] 3727Å line flux (1)
22- 27 F6.4 --- O2-3729 The [O II] 3729Å line flux (1)
29- 34 F6.4 --- Ne3-3869 The [Ne III] 3869 line flux (1)
36- 41 F6.4 --- S2-4068 The [S II] 4068,78 line flux (1)
43- 48 F6.4 --- Hg The Hγ 4340 line flux (1)
50- 55 F6.4 --- O3-4363 The [O III] 4363 line flux (1)
57- 62 F6.4 --- He1-4471 The He I 4471 line flux (1)
64- 69 F6.4 --- Hb [1] The Hβ 4861 line flux (1)
71- 76 F6.4 --- O3-4959 The [O III] 4959 line flux (1)
78- 83 F6.4 --- O3-5007 The [O III] 5007 line flux (1)
85- 90 F6.4 --- He1-5016 The He I 5016 line flux (1)
92- 97 F6.4 --- Ar3-5192 The [Ar III] 5192 line flux (1)
99-104 F6.4 --- N1-5198 The [N I] 5190,00 line flux (1)
106-111 F6.4 --- N2-5755 The [N II] 5755 line flux (1)
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Note (1): Relative to FHβ = 1.0.
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 F4.2 Sun Z [0.05/5] Model metallicity (relative to Sun)
6- 7 I2 --- kappa [10/50]? Model κ value
8 A1 --- f_kappa [i] i: infinite (kappa is blank)
10- 13 F4.2 [m/s] logq [6.5/8.5] Model ionization parameter (G1)
15- 20 F6.4 --- He1-5875 The He I 5875Å line flux (1)
22- 27 F6.4 --- O1-6300 The [O I] 6300Å line flux (1)
29- 34 F6.4 --- S3-6313 The [S III] 6312Å line flux (1)
36- 41 F6.4 --- N2-6548 The [N II] 6548Å line flux (1)
43- 48 F6.4 --- Ha The Hα line flux (1)
50- 55 F6.4 --- N2-6584 The [N II] 6584Å line flux (1)
57- 62 F6.4 --- He1-6678 The He I 6678Å line flux (1)
64- 69 F6.4 --- S2-6717 The [S II] 6717Å line flux (1)
71- 76 F6.4 --- S2-6731 The [S II] 6731Å line flux (1)
78- 83 F6.4 --- Ar3-7136 The [Ar III] 7136Å line flux (1)
85- 90 F6.4 --- O2-7318 The [O II] 7318Å line flux (1)
92- 97 F6.4 --- Ar3-7751 The [Ar III] 7751Å line flux (1)
99-104 F6.4 --- S3-9068 The [S III] 9068Å line flux (1)
106-111 F6.4 --- S3-9532 The [S III] 9532Å line flux (1)
--------------------------------------------------------------------------------
Note (1): Relative to FHβ = 1.0.
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Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 F4.2 Sun Z [0.05/5] Model metallicity (relative to Sun)
6- 7 I2 --- kappa [10/50]? Model κ value
8 A1 --- f_kappa [i] i: infinite (kappa is blank)
10- 13 F4.2 [m/s] logq [6.5/8.5] Model ionization parameter (G1)
15- 19 I5 K TH [1916/14450] Hydrogen model temperature
21- 25 I5 K THe [1994/14270] Helium model temperature
27- 31 I5 K TO3 [4613/16577]? The [O III] model temperature
33- 37 I5 K TAr3 [4256/14070]? The [Ar III] model temperature
39- 43 I5 K TS3 [2804/13886]? The [S III] model temperature
45- 49 I5 K TO2 [2987/12506]? The [O II] model temperature
51- 55 I5 K TN2 [2833/12655]? The [N II] model temperature
57- 60 I4 K TS2 [2373/8451] The [S II] model temperature
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Global Notes;
Note (G1): the ionization parameter Υ measures the ratio of the
density per unit volume of ionizing photons to the particle (atom plus
ion) number density. In this paper, we use the alternative definition,
q, which is defined as the ratio of the number of ionizing photons
impinging per unit area per second divided by the gas particle number
density. The transformation between the two definitions is simply
q=Υc, c being the speed of light.
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 02-Oct-2013