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

icf_argon(O_plus, O_total)

ICF for argon (Izotov+06 eqs.

icf_carbon(O_plus, O_pp)

ICF for carbon (Garnett+1997).

icf_neon(O_plus, O_total)

ICF for neon (Izotov+06 eq.

icf_nitrogen(O_plus, O_total)

ICF for nitrogen (Izotov+06 eq.

icf_sulfur(O_plus, O_total)

ICF for sulfur (Izotov+06 eq.
jwspecabund.icf.icf_argon(O_plus, O_total)[source]

ICF for argon (Izotov+06 eqs. 22/23).

Ar/O = ICF_Ar * Ar++/O++.

Parameters:

  • O_plus (float) – Ionic abundance O+/H+.

  • O_total (float) – Total oxygen abundance O/H.

Returns:

ICF_Ar.

Return type:

float

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+

Parameters:

  • O_plus (float) – Ionic abundance O+/H+.

  • O_pp (float) – Ionic abundance O++/H+.

Returns:

ICF_C. Returns 1.0 when O+ is negligible or not detected.

Return type:

float

jwspecabund.icf.icf_neon(O_plus, O_total)[source]

ICF for neon (Izotov+06 eq. 19).

Ne/O = ICF_Ne * Ne++/O++.

Parameters:

  • O_plus (float) – Ionic abundance O+/H+.

  • O_total (float) – Total oxygen abundance O/H.

Returns:

ICF_Ne.

Return type:

float

jwspecabund.icf.icf_nitrogen(O_plus, O_total)[source]

ICF for nitrogen (Izotov+06 eq. 18).

N/O = ICF_N * N+/O+, where ICF_N accounts for the contribution of higher ionisation states of nitrogen.

Parameters:

  • O_plus (float) – Ionic abundance O+/H+.

  • O_total (float) – Total oxygen abundance O/H (= O+/H+ + O++/H+).

Returns:

ICF_N. Returns 1.0 for the standard assumption N/O ~ N+/O+.

Return type:

float

jwspecabund.icf.icf_sulfur(O_plus, O_total)[source]

ICF for sulfur (Izotov+06 eq. 20).

S/O = ICF_S * (S+ + S++)/O.

Parameters:

  • O_plus (float) – Ionic abundance O+/H+.

  • O_total (float) – Total oxygen abundance O/H.

Returns:

ICF_S.

Return type:

float