VLA RADIO RECOMBINATION LINE OBSERVATIONS OF SAGITTARIUS A WEST

With a resolution of 2″.4 and an r.m.s. noise of 0.4 mJy beam -1, the northern arm and bar of Sagittarius A (Sgr A) West have been observed in the H92α radio recombination line (RRL) at 8.3 GHz using the Very Large Array (VLA). Zeeman observations of several positions in the northern arm have yielded upper limits of 15 mG (3 σ) for the line-of-sight magnetic field. In the bar region within 30″ of Sgr A *, the increase in electron temperature suggested by van Gorkom, Schwarz, & Bregman in 1985, has been confirmed. Values of the electron temperature in the range 20,000-40,000 K are observed. The H92α spectra have similar shapes to those of [Ne II] at 12.8 μm; thus, pressure broadening is not important in influencing the line widths of these highfrequency recombination lines.