brighter than our Sun) ionizes nearby gases, causing them to emit radio waves. Only the inner, hottest regions of the nebula are repre- sented in this image; the more extended structures seen in visible light are not hot enough to produce detectable levels of bremsstrahlung radiation.
As the radio image shows, the re- gion of most intense star formation is in the lower band (radio emis- sions are much stronger here than in the upper band). Although both regions appear in infrared light, it is difficult to tell at that wavelength which in fact contains the hottest stars. Interestingly, the strongest radio emission comes from a region that is less obscured by dust than others. Even so, the hot stars that generate the emission are
