Masers in the cool molecular cloud L 379

We present the results of monitoring the H2O masers in the IR sources WAS 18265-1517 and IRAS 18277-1516 associated with the cool molecular cloud L 379, which contains high-velocity bipolar molecular jets. The sources were observed in the 1.35 cm H2O line using the 22-m radio telescope of the Pushchino Radio Astronomy Observatory (Russia) during 1991-2004. We detected H2O maser emission from WAS 18265-1517 at radial velocities of 17.8 and 18.4 km/s, virtually coincident with the velocity of the molecular Cloud derived from CO-line observations (18.4 km/s). The maser emission towards the other source, WAS 18277-1516, was at higher velocities than the central velocity of the CO molecular cloud. The H2O maser spots are most likely associated with a redshifted region of CO emission. Cyclic variability of the integrated H2O maser emission that may be related to cyclic activity of the central star was detected for WAS 18277-1516. The strongest and most long-lived component (V-LSR approximate to Z- 20.6 km/s) displays a radial-velocity drift, which could be due to deceleration of a dense clump of matter (maser condensation) in the circumstellar medium during the descending branch of a strong flare. We found numerous emission features for both WAS 18265-1517 and WAS 18277-1516, providing evidence for fragmentation of the medium surrounding their central objects. (c) 2005 Pleiades Publishing, Inc.