330-MHZ RADIO-CONTINUUM IMAGING OF THE W51 COMPLEX

We present a 1.1-arcmin-resolution image of the W51 complex made with the Very Large Array at a frequency of 330 MHz. W51A and W51B are reso lved into multiple components at metre wavelengths for the first time: most of the compact components have spectra that are self-absorbed at this low observing frequency and these components appear surrounded b y thermal plasmas with low emission measures. We estimate the electron temperature towards the brightest subcomponent of W51A (G49.5-0.4e) t o be >7500K. This temperature estimate is consistent with inferences f rom observations of radio recombination lines from the H II region: th ere is no evidence in our image for a radial temperature decrement wit hin the subcomponent.