The narrow line emission region: photo ionized disk atmosphere or illuminated face of the donor HZ?
1)Thermal and ionization balance Þ upper limit on
the e density;
2)EM from line fluxes Þ lower limits on the e density;
3)Hea line ratios and
UV photo excitation calculations Þ upper limits to the radius enclosing the region;
Confidence limits (90%) on density and location of the narrow line emission
region, obtained from spectroscopic analysis and modelling.
The limits shown correspond to O VII, and similar limits with N VI and Ne IX can be set