E. E. Lekht, M. I. Pashchenko, G. M. Rudnitskii
Results of monitoring the H$_2$O and OH masers in W44C, located near the
cometary HII region G34.3+0.15, are reported. Observations in the water-vapor
line at $\lambda = 1.35$ cm were carried out on the 22-meter radio telescope of
the Pushchino Radio Astronomy Observatory (Russia) from November 1979 to March
2011, and in the hydroxyl lines at $\lambda = 18$ cm on the Large Nan{\c{c}}ay
radio telescope (France). Activity maxima and minima of the water maser
alternated. The average period of the activity is $\sim 14$ years, consistent
with results obtained earlier for a number of other sources associated with
regions of active star formation. In periods of enhanced maser activity, two
series of strong H$_2$O maser flares were observed, which were related to two
different clusters of maser spots located at the front of a shock at the
periphery of the ultracompact region UH II. These series of flares may be
associated with cyclic activity of the protostellar object in UH II. In the
remaining time intervals, there were mainly short-lived flares of single
features. The Stokes parameters for the observations in the hydroxyl lines were
determined. Zeeman splitting was observed in the profile of the 1667 MHz OH
main line at a velocity of 58.5 km/s, and was used estimate the intensity of
the line-of-sight component of the magnetic field (1.2 mG).
View original:
http://arxiv.org/abs/1111.4961
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