Radio Continuum Structure of the Orion Nebula

Abstract

We have imaged the large-scale radio continuum structure in the Orion region with the Very Large Array at 330 MHz. Arcminute-resolution morphology of the extended emission in the H II regions M42 and M43 (NGC 1976 and NGC 1982) and in the NGC 1973-75-77 nebulosity to the north are presented. A low surface brightness thermal radio halo is detected in the H II region M42: comparison with an optical photograph indicates that the radio emission distinguishes optical emission structures from reflection nebulosities. In NGC 1977 we have discovered a compact, steep-spectrum radio source coincident with a bright optical rim.