Detection of CH3OH J = 5 to 4 lines around 242 GHz from OMC-1

Abstract

Sixteen methanol lines have been detected at a frequency of 242 GHz from OMC-1. They correspond to the J = 5..-->..4, ..delta..k = 0 transitions of CH/sub 3/OH A and E. With the assumption of reproduced with a thermal excitation model using one temperature, T/sub exc/ = 90 K, and using a column density of N(CH/sub 3/OH) = 5 x 10/sup 16/ cm/sup -2/. All lines appear to be optically thin. Collisional excitation of the J = 5 levels requires gas densities of n(H/sub 2/)> or =4 x 10/sup 6/ cm/sup -3/. Some of the detected methanol lines are also observed at a position 2' south of OMC-1 and in DR 21, M17(SW), and W3(OH).