PHYSICAL PROPERTIES OF THE ORION KL SUPER WATER MASER IN “QUIESCENT” PHASE

Abstract

The observations of the water vapor maser emission toward the Orion - KL nebala have been carried out with the 13.7 m radio telascope at Delingha station of Purple Mountain Observatory. The maser emission is characterized by the "quiescent phase" with the peak flux density 3×104Jy, two orders lower than that during the "outburst phase". The maser action in the "quiescent phase" is full saturated with the quiescent level of brightness temperature 3×1013 K. On the assumption of spherical maser and the saturated state, the hydrogen density of 8 × 1014(H2)m-3 and the population inversion of 5×105(H2O)m-3 in the masing region are derived.The Orion super water vapor maser spectrum consists of emission in three symmetric velocity intervals centered at the velocity 10 km·s-1. This may imply that there are symmetric outflows or expanding shells with constant velocities in the masing region.