Line imaging of Orion KL at 865 μm with the submillimeter array

We present the first submillimeter (865 mu m) imaging spectral line survey at 1 '' resolution conducted with the Sub-millimeter Array toward Orion KL. Within the 2 x 2 GHz bandpasses ( lower and upper sidebands, 337.2 - 339.2 and 347.2 - 349.2 GHz), we find about 145 spectral lines from 13 species, six isotopologues, and five vibrational excited states. Most nitrogen-bearing molecules are strong toward the hot core, whereas the oxygen-bearing molecules peak toward the southwest in the so-called compact ridge. Imaging of spectral lines is shown to be an additional tool to improve the identifications of molecular lines. Arcsecond spatial resolution allows us to distinguish the molecular line emission of the sources I and n from that of the hot core. The only molecular species detected strongly toward source I is SiO, delineating mainly the collimated northeast- southwest low- velocity outflow. The two positions close to source I, which have previously been reported to show maser emission in the v = 0 (28)SiO (1 - 0) and (2 - 1) lines, show no detectable maser emission in the v =0 (28)SiO (8 - 7) line at our spatial resolution. SiO is weak toward source n, and thus source n may not currently be driving a molecular outflow. CH(3)OH is the molecule with the highest number of identified lines (46) in this spectral window. This ''line forest'' allows us to estimate temperatures in the region, and we find temperatures between 50 and 350 K, with the peak temperatures occurring toward the hot core. The detection of strong vibrational excited line emission from the submillimeter continuum peak SMA1 supports the interpretation that the source SMA1 is likely of protostellar nature.