jwspecabund.icf
Ionisation correction factors.
References
Izotov, Y. I., Stasinska, G., Meynet, G., Guseva, N. G., & Thuan, T. X. 2006, A&A, 448, 955. Equations 18–23.
Garnett, D. R., Shields, G. A., Skillman, E. D., Sagan, S. P., & Dufour, R. J. 1997, ApJ, 489, 63.
Functions
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ICF for argon (Izotov+06 eq. |
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ICF for carbon (Garnett+1997). |
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ICF for neon (Izotov+06 eq. |
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ICF for nitrogen (Izotov+06 eq. |
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ICF for sulfur (Izotov+06 eq. |
- jwspecabund.icf.icf_argon(O_plus, O_total)[source]
ICF for argon (Izotov+06 eq. 22).
Elemental correction from Ar++ alone: Ar/H = ICF_Ar * Ar++/H+, accounting for unseen Ar+ and Ar+++. To form Ar/O, divide by the total oxygen abundance: Ar/O = ICF_Ar * (Ar++/H+) / (O/H). Izotov+06 eq. 22 is a fit in v = O+/(O+ + O++), with three metallicity branches.
- jwspecabund.icf.icf_carbon(O_plus, O_pp)[source]
ICF for carbon (Garnett+1997).
When C+ is not detected, the observed (C2+ + C3+)/O2+ underestimates C/O because C+ in the low-ionisation zone is missing. The correction assumes C+/C_total ~ O+/O_total (similar ionisation structure):
C/O = ICF_C * (C2+ + C3+) / O2+ ICF_C = (O+ + O2+) / O2+
- jwspecabund.icf.icf_neon(O_plus, O_total)[source]
ICF for neon (Izotov+06 eq. 19).
Elemental correction: Ne/H = ICF_Ne * Ne++/H+. To form Ne/O, divide the corrected Ne abundance by the total oxygen abundance, i.e. Ne/O = ICF_Ne * (Ne++/H+) / (O/H).
- jwspecabund.icf.icf_nitrogen(O_plus, O_total)[source]
ICF for nitrogen (Izotov+06 eq. 18).
Elemental correction: N/H = ICF_N * N+/H+. To form N/O, divide the corrected nitrogen abundance by the total oxygen abundance, i.e. N/O = ICF_N * (N+/H+) / (O/H). Izotov+06 eq. 18 is a fit in the O+ ionisation fraction v = O+/(O+ + O++), with three metallicity branches.