SIMBAD references

We have used the Wisconsin Hα Mapper facility to measure the [O I] λ6300/Hα line intensity ratios for four O star H II regions: S27 (observation coordinates l=6°.3,b=+23°.6), S252 (l=190°.1,b=+0°.6), S261 (l=194°.1,b=-1°.9), and S264 (l=195°.1,b=-12°.0). We find that the ratios range from 0.0015 to 0.0053. These results are roughly a factor of 10 lower than measured [O I]/Hα ratios in directions that sample the warm ionized component of the interstellar medium. This difference implies a significantly lower hydrogen ionization ratio n(H⁺)/n(H⁰) or higher electron temperature in the diffuse ionized gas compared with that in the bright discrete O star H II regions.