Ionized gas in Sagittarius B2 Main on scales of 0.065 arcseconds (600 AU)

The ionized gas in the Sagittarius B2 Main star-forming region has been imaged with similar to 65 mas (600 AU) resolution using the Very Large Array (VLA) at 7 mm in the A configuration. These observations have similar to 4-5 times the resolution of the previous highest resolution images of this source. These VLA observations show that the central four ultracompact H II (UC H II) regions in Sgr B2 Main (F1, F2, F3, and F4) break up into similar to 20 separate UC H II regions. The individual sources have small resolved sizes (similar to 10(-3) pc), high derived emission measures (EM similar to 10(9) pc cm(-6)), and high rms electron densities (n(e) similar to 10(6) cm(-3)). We compare the observed radius and derived emission measure of each of these regions with those expected for a UC H II region in pressure equilibrium with its environment, using previously published temperatures and densities for the Sgr B2 molecular core (n(H2) = 2 x 10(7) cm(-3)). We find that the observed emission measures are in fact higher than those predicted in a simple pressure-confinement model, suggesting that the molecular densities on scales that confine the UC H II regions may be higher than 2 x 10(7) cm(-3).