Evolution of OH and H2O Maser Emission in the Active Star Formation Region NGC 2071

Abstract

We present the observation results of the star forming region NGC 2071 in the 1.35-cm H2O line and 18-cm OH lines obtained with the 22-m radio telescope in Pushchino (Russia) and the large radio telescope in Nancay (France), respectively. The catalog of H2O maser emission spectra from December 2010 to January 2020 is given. The total flux variability for the entire monitoring period (1979–2020) has two activity cycles of close duration (approximately 20 years), which were accompanied by strong flares at intervals of one to four years. It is shown that the medium for the generation of H2O maser emission is greatly fragmented and contains small-scale turbulent motions of matter. The observed drift and radial velocity jumps of the H2O emission features can be a consequence of the complex, inhomogeneous structure of the maser emission regions. OH emission in the 1665 and 1667 MHz main lines and in the 1612 MHz satellite line in the radial velocity range of 7–12 km/s is broadband. The ratio of intensities differs from equilibrium. The substantiation of the observed ratio between the intensities of this emission and absorption in the 1720 MHz line is given. OH maser emission was observed in 2007 in the left circular polarization in the 1667 MHz line at 13.02 and 13.55 km/s with a flux density of ~0.3 Jy and a width of ~0.25 km/s for each of the velocities.