2014ApJ...795...13B

Using the IRAM 30 m telescope, we have surveyed a 1x0.°8 part of the Orion molecular cloud in the ¹²CO and ¹³CO (2-1) lines with a maximal spatial resolution of ∼11'' and spectral resolution of ∼0.4 km/s. The cloud appears filamentary, clumpy, and with a complex kinematical structure. We derive an estimated mass of the cloud of 7700 M_☉(half of which is found in regions with visual extinctions A_V below ∼10) and a dynamical age for the nebula of the order of 0.2 Myr. The energy balance suggests that magnetic fields play an important role in supporting the cloud, at large and small scales. According to our analysis, the turbulent kinetic energy in the molecular gas due to outflows is comparable to turbulent kinetic energy resulting from the interaction of the cloud with the H II region. This latter feedback appears negative, i.e., the triggering of star formation by the H II region is inefficient in Orion. The reduced data as well as additional products such as the column density map are made available online (http://userpages.irap.omp.eu/~oberne/Olivier_Berne/Data).