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Table B.3.

Wavelengths and ionisation potential of the relevant ion for each emission line.

Line name Wavelength String ID Ionisation potential Fixed ratio
(air) [Å] [eV]
Hydrogen Balmer lines

Hβ 4861.35 HB4861 13.60 no
Hα 6562.79 HA6562 13.60 no

Low ionisation lines

[N II]λ5197 5197.90 NI5197 no
[N II]λ5200 5200.26 NI5200 no
[N II]λ5754 5754.59 NII5754 14.53 no
[N II]λ6548 6548.05 NII6548 14.53 0.34 [N II]λ 6584
[N II]λ6584 6583.45 NII6583 14.53 no
[S II]λ6717 6716.44 SII6716 10.36 no
[S II]λ6731 6730.82 SII6730 10.36 no

High-ionisation lines

He IIλ4686 4685.70 HEII4865 24.58 no
[O III]λ4959 4958.91 OIII4958 35.12 0.35 [O III]λ 5007
[O III]λ5007 5006.84 OIII5006 35.12 no
He Iλ5876 5875.61 HEI5875 no
[S III]λ6312 6312.06 SIII6312 23.34 no

Notes. Wavelengths are taken from the National Institute of Standards and Technology (NIST; https://physics.nist.gov/PhysRefData/ASD/lines_form.html), and are Ritz wavelengths in air except for the H Balmer lines, in which case we use the ‘observed ’ wavelength in air as reported in NIST. The DAP string name is used to identify the correct extension in the MAPS files or in the moment maps. Ionisation potentials are taken from Draine (2011). The [O I] lines at 6300 and 6363 Å are not included in this list because they are heavily contaminated by sky emission.

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