RADIO-CONTINUUM OBSERVATIONS OF SGR-E

The group of compact sources in the direction of the Galactic Centre (l = 358.7-degrees, b = 0-degrees) known as Sgr E has been observed with the Molonglo Observatory Synthesis Telescope at 843 MHz and with the Very Large Array at 1.45 and 4.86 GHz. There are 70 discrete sources in the complex having integrated flux densities S1.4 GHz greater than or similar to 4 mJy, confined to an area of approximately 0.40 deg2. We determine the radio spectra of 34 of the sources. Of these, most have spectral indices (1.45/4.86 GHz) consistent with H II regions. Simple models of the compact H II regions and the associated molecular cloud suggest that the complex contains about 20 OB stars, some 2000 M. of ionized gas, about 10(4) M. of stellar mass, and about 2 x 10(6) M. of Molecular gas. A small proportion of the sources with measured indices have steep spectra (alpha < -0.5; S is-proportional-to nu(alpha)), and upper limits on S4.86 for several other sources imply steep spectra. The surface density of steep-spectrum sources and their distribution of flux densities are consistent with all of them being extragalactic, and none is an obvious supernova candidate. Sgr E is coincident with a region exhibiting a high line-of-sight velocity (-200 km s-1) and lying close to the Galactic Centre. It may represent a small burst of star formation in part of a circumnuclear disc or in matter ejected from the Galactic nucleus. The absence of supernovae indicates an age less than approximately 5 Myr.