Evolution of the OH and H2O Maser Emission in the Active Star-Forming Region IRAS 05358+3543 (S231)статья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 25 ноября 2020 г.
Аннотация:We present the results of our observations of the star-forming region located in the Perseus arm andassociated with the Sharpless nebula S231 in the lines of H2O at a wavelength of 1.35 cm and OH at a wavelengthof 18 cm obtained with the Pushchino 22-m radio telescope (Russia) and the Nançay Large RadioTelescope (France), respectively. We provide a catalog of H2O maser spectra in the period from March 2003to March 2020. The variability of the integrated flux that we have calculated based on the monitoring by Felliet al. (1987–2007) and our monitoring (2003–2020) has a quasi-cyclic pattern with a cycle duration from4.3 to 7.7 yr. Flares of maser emission of both single and several features occurred in each activity cycle. Themean rise and decay times of the flare emission were 0.30 and 0.35 yr, respectively. Theobserved radial velocity drift and jumps of the H2O emission features can be a consequence of the impact ofshocks emerging as the protostar activity rises on them. The complex pattern of variability shows that the H2Omasing medium is fragmented and small-scale turbulent motions of matter can occur in it. We have observedthe OH maser emission in the 1665 and 1667 MHz main lines and the 1720 MHz satellite line. A large numberof OH emission features and their variability have been detected. We have found one Zeeman pair at‒9.2 km/s with a small splitting, with the longitudinal magnetic field in the period 2008–2020 havingdecreased monotonically from 0.24 to 0.10 mG. For the three most intense features we have calculated thedegrees of linear polarization and position angles. A correlation between the H2O and OH maser activities hasbeen found.