Physical Conditions in Shocked Regions of Orion from Ground-based Observations of H[TINF]2[/TINF]O

We present observations of the 5$_{1,5} o4_{2,2}$ transition of water vapor at 325.15 GHz taken with the CSO telescope towards Orion IRc2. The emission is more extended than that of other molecular species such as CH$_3$OH. However, it is much less extended than the emission of water vapor at 183.31 GHz reported by Cernicharo et al (1994). A comparison of the line intensities at 325.15 GHz and 183.31 GHz puts useful constraints on the density and temperature of the emitting regions and allows an estimate of H_2O abundance, x(H_2O), of $simeq10^{-4}$ in the Plateau and $simeq10^{-6}-10^{-5}$ in the Ridge.Comment: 4 figure