Table 6: Parameters of the model density distribution, fitted on the slit H $\beta$ profile and on the image. The distances are expressed in 10²⁰ cm, and the densities in cm^-3. ^a Projected minor and major semi-axes. ^b Projected distance to the source.
Parameter Slit value Image value

R₁ 1.01 0.97 $\times$ 1.61^a

R₂ 1.24 1.19 $\times$ 1.98^a

R₃ 2.49 2.39 $\times$ 3.99^a

N₁ 4.81 6.13

N₂ 9.13 10.9

N₃ 5.09 6.04

R_G^b 0.40 0.40

$\sigma_G$ 0.17 0.17

N_G 40.3 40.3

**Table 6:** Parameters of the model density distribution, fitted on the slit H $\beta$ profile and on the image. The distances are expressed in 10²⁰ cm, and the densities in cm^-3. ^a Projected minor and major semi-axes. ^b Projected distance to the source.
Parameter	Slit value	Image value
R₁	1.01	0.97 $\times$ 1.61^a
R₂	1.24	1.19 $\times$ 1.98^a
R₃	2.49	2.39 $\times$ 3.99^a
N₁	4.81	6.13
N₂	9.13	10.9
N₃	5.09	6.04
R_G^b	0.40	0.40
$\sigma_G$	0.17	0.17
N_G	40.3	40.3

Source LaTeX | All tables | In the text

	1 Introduction
	2 Observational data and reduction
	3 Empirical diagnostics
	4 General strategy for model fitting
	5 Simple models
	6 Models with constrained density distribution
	7 Further refining of the models
	8 Sources of energy other than the ionizing flux
	9 Uncertainties in O/H and Ne/O
	10 Conclusion
	References
	Online Material
	Appendix A: Correction of Balmer lines used for dereddening
	Appendix B: Setting the geometric corrections A, B, and K