Large-scale structure, kinematics, and heating of the Orion Ridge

We present a high resolution VLA study of the 1.0 pc extended OMC-1 molecular ridge surrounding the Orion BN/KL core of high mass star formation. We have mapped the NH{dollar}sb3{dollar} (1,1) and (2,2) rotation-inversion lines over 20 adjacent fields covering a 3{dollar}spprime{dollar} by 8{dollar}spprime{dollar} region encompassing the Kleinman-Low (KL) nebula, with high (0.3 km s{dollar}sp{lcub}-1{rcub}){dollar} velocity resolution and high (9{dollar}sp{lcub}primeprime{rcub}){dollar} angular resolution. We present a linear mosaic of these fields, showing an abundance of structural, kinematical, and temperature information. Techniques and challenges encountered while mosaicing the interferometric maps are discussed. We find extended clumpy filaments throughout the region. We present the first high resolution temperature map of the ridge, and find a striking pattern of interclump and edge heating. Radiation from foreground O and B stars may be penetrating the clumpy medium and heating the sheaths around the cores. There is evidence for large scale (0.5 pc) outflows originating from the KL core and extending along the filaments, possibly shredding and shaping the filaments while heating their edges. The component fragments along the molecular filaments display velocity gradients; some may be sites of young stars or collapsing cores which have not yet shed their angular momentum. We also find material with velocities differing by more than 2 km s{dollar}sp{lcub}-1{rcub}{dollar} present within small projected areas, complicating simple global rotation models for OMC-1. Two major velocity components appear to overlap in the BN/KL active core region, suggesting cloud collision as a possible triggering mechanism. We discuss the likelihood of instability and fragmentation along the filaments. A quantitative method of analyzing the morphological complexity of molecular clouds is developed and applied to IRAS maps of five clouds. The clouds are then ordered according to their complexity, and this ordering is related to the properties of internal star formation. These observations provide evidence for extensive and long-range interaction between a core of high mass star formation and its molecular cloud environment.