Table 6.

Diagnostic line ratios

Ion	Lines	Ratio	Determines	Notes
[N i]	I(λ5200)/I(λ5198)	0.47	Nɛ	N/A?
[N ii]	I(λ6548 + λ6583)/I(λ5755*)	21.6	Tɛ
[O iii]	I(λ4959 + λ5007)/I(λ4363)	52.2	Tɛ
[S ii]	I(λ6716‡)/I(λ6731)	0.45	Nɛ
[S iii]	I(λ9069 + λ9531†)/I(λ6312)	14.3	Tɛ
[Ar iii]	I(λ7136 + λ7751)/I(λ5191*)	84.7	Tɛ
[Ar iv]	I(λ4711)/I(λ4740)§	0.54	Nɛ
[Ar iv]	I(λ4711 + 40)/I(λ7170)	16.7	Nɛ, Tɛ
[Cl iii]	I(λ5538)/I(λ5518)	2.18	Nɛ

N/A?, Useless because of its poor measurement. 

^*Relatively weak line. 

^†Affected by atmospheric extinction. 

^‡Affected by Hα drip (correction was made). 

^§See Keenan et al. (19).