VERY HOT IONIZED MATERIAL IN SAGITTARIUS-B2-F

VLA 20 cm continuum observations (2'' x 1'' resolution) of the Sgr B2 star-forming region have been carried out. The peak intensity, which o ccurs at the location of the Sgr B2 F complex of H II regions, corresp onds to a brightness temperature of 23,000 K. The continuum spectrum a ppears to be thermal; thus the brightness temperature provides a lower limit to the electron temperature. The H66 alpha recombination lines (v = 22.4 GHz) in this region also suggest that the temperature is hig h. The LTE electron temperature derived from the H66 alpha data is 19, 600 K. It is unclear what the heating mechanism is, although a highly nonequilibrium situation which occurs at the edge of the expanding ion ization front might be responsible.