Abstract
In the Milky Way's diffuse ionized gas, helium is observed to be underionized relative to hydrogen, implying ionization by a softer radiation field than typical of H (II) regions. We construct 3D photoionization models of the diffuse ionized gas and show that the ionizing spectra escaping from leaky H it regions can provide a solution to the He+/H+ problem. Depending on the spectral type of the ionizing source(s) and the fractional leakage from the H it region, we find that leaky spectra are harder and have their He-ionizing photon luminosity supressed. Such spectra yield a reduced He+/H+ fraction and increased heating compared to normal stellar spectra.
| Original language | English |
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| Title of host publication | HOW DOES THE GALAXY WORK? |
| Editors | EJ Alfaro, E Perez, J Franco |
| Place of Publication | DORDRECHT |
| Publisher | Springer |
| Pages | 83-87 |
| Number of pages | 5 |
| ISBN (Print) | 1-4020-2619-6 |
| Publication status | Published - 2004 |
| Event | International Conference on How Does the Galaxy Work - Granada Duration: 23 Jun 2003 → 27 Jun 2003 |
Conference
| Conference | International Conference on How Does the Galaxy Work |
|---|---|
| City | Granada |
| Period | 23/06/03 → 27/06/03 |