Mid-J CO emission from the Orion BN/KL explosive outflow

High spatial resolution low-J (CO)-C-12 observations have shown that the wide-angle outflow seen in the Orion BN/KL region correlates with the famous H-2 fingers. Recently, high-resolution large-scale mappings of mid-and higher-J CO emissions have been reported toward the Orion molecular cloud 1 core region using the APEX telescope. Therefore, it is of interest to investigate this outflow in the higher-J (CO)-C-12 emission, which is likely excited by shocks. The observations were carried out using the dual-color heterodyne array CHAMP(+) on the APEX telescope. The images of the Orion BN/KL region were obtained in the (CO)-C-12 J = 6-5 and J = 7-6 transitions with angular resolutions of 8 ''.6 and 7 ''.4, respectively. The results show a good agreement between our higher-J (CO)-C-12 emission and SMA low-J (CO)-C-12 data, which indicates that this wide-angle outflow in Orion BN/KL is likely the result of an explosive event that is related to the runaway objects from a dynamically decayed multiple system. From our observations, we estimate that the kinetic energy of this explosive outflow is about 1-2 x 10(47) erg. In addition, a scenario has been proposed where part of the outflow is decelerated and absorbed in the cloud to explain the lack of CO bullets in the southern part of BN/KL, which in turn induces the methanol masers seen in this region.