High-Resolution Observations of the Orion Bright Bar

High resolution strip maps of CS (J = 1–0) and H51α line emission across the Orion bright bar are presented. They reveal the existence of a high density molecular layer (molecular sheet) plane parallel to the ionization front. This molecular sheet is redshifted relative to the ambient molecular cloud by about 2 km s − 1. The rapid decrease of the CS emission at about 50 arc sec from the bar suggests that a shock front exists here and the sheet is a post shock layer.