Back to the Abstract

	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

	List of tables
	List of figures