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Session 53 - SNs, Planetaries and Circumstellar Disks.
Display session, Wednesday, June 10
Atlas Ballroom,

[53.16] OH 1720 MHz Masers in Supernova Remnants --- C-Shock Indicators

P. Lockett (Centre College), E. Gauthier (Johns Hopkins University), M. Elitzur (U.Kentucky)

Recent observations have shown that the OH 1720 MHz maser is a powerful probe of the shocked region where a supernova remnant strikes a molecular cloud. We have performed a thorough study of the pumping of this maser and have found tight constraints on the physical conditions needed for its production. The presence of the maser implies low temperatures (50 -- 150 K), low molecular densities (\sim 10^5cm^-3) and OH column densities of the order of 10^16cm^-2. We show that these conditions can exist only if the shocks are of C-type, thus the presence of this maser is a powerful shock diagnostic. These conditions also mean that the 1720 maser will be inherently weak compared to the other ground state OH masers. All the model predictions are in good agreement with the observations.

Program listing for Wednesday