Carbon recombination-line mapping of the Orion Nebula

The distribution of the C75..cap alpha.. line in the Orion Nebula was mapped with a spatial resolution of 1'.3 over a field of view of ..cap alpha.. x delta = 4' x 8'. Ionized carbon is more extended than the radio continuum distribution, particularly to the northeast, and possibly also beyond the ionization front in the southeast; however, the emission falls off across the ionization front northwest of the nebula. The emission is generally consistent with a model in which the line is formed in a thin sheet in the molecular cloud immediately adjacent to the H II region. However, the spatial extent of the emission does suggest that some of the emitting gas may be cooler and less dense than has previously been assumed. 4 figures, 1 table.