Comparison of H II region Luminosities with Observed
Stellar Ionizing Sources in the Large Magellanic Cloud
M.S. Oey & R.C. Kennicutt, Jr.
We estimate the total predicted Lyc emission rates of
OB associations for which the complete census of O star
spectral types exist. The results are compared to the observed
H-alpha luminosities of the host H II regions. We find evidence for
substantial leakage of ionizing photons from some H II regions, while
others appear to be radiation bounded. We estimate that overall for
the LMC, 0-51% of the ionizing radiation escapes the local
nebulae, and would be available to ionize the diffuse, warm,
ionized medium (WIM) in that galaxy. This range of
values is consistent with the observed 35% fraction of
H-alpha luminosity emitted by the WIM in the LMC, as well as
the corresponding fractions observed in other nearby galaxies.
It is therefore possible that photoionization by O stars is indeed
the dominant ionization mechanism for the WIM.
1997 MNRAS, 291, 827
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