Observations of Hydroxyl in the Onsala 1 Source at 18 cm

Abstract

We present results of polarization observations of the ON 1 source in the 1665, 1667, and 1612 MHz hydroxyl lines at the Large Radio Telescope in Nançay (France). Spatial identification of the spectral features of OH in the 1665 and 1667 MHz lines with maser spots (condensations) on the VLBI map according to the data of Fish et al. (2005) was carried out. Emission from hitherto unknown spectral features in the 1665 MHz main line at radial velocities of –2.98, 9.35, and 11.8 km/s has been detected. Five Zeeman pairs were found: four in the 1665 MHz line and one in the 1667 MHz line. The vectors of the transverse magnetic field H⊥ are oriented mainly along the arc (in the upper and lower parts of the UC H II region), while the vectors of the longitudinal magnetic field H|| in the northern and central parts of the UC H II region are oriented away from the observer, while in the southern part toward the observer.