Investigation of OH and H₂O masers in the star-forming region G 188.946+0.886

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• 作者：N. T. Ashimbaeva ; P. Colom ; E. E. Lekht ; M. I. Pashchenko…
• 关键词：star formation ; masers ; magnetic field ; individual objects (G 188.946+0.886)
• 刊名：Astronomy Letters
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：42
• 期：10
• 页码：652-664
• 全文大小：2,582 KB
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Astronomy
  Astrophysics
  Russian Library of Science
  
• 出版者：MAIK Nauka/Interperiodica distributed exclusively by Springer Science+Business Media LLC.
• ISSN：1562-6873
• 卷排序：42

文摘

We present the results of our observations of the maser radio emission source G188.946+0.886 in hydroxyl (OH) molecular lines with the radio telescope of the Nançay Observatory (France) and in the H₂O line at λ = 1.35 cm with the RT-22 radio telescope at the Pushchino Observatory (Russia). An emission feature in the 1720-MHz satellite line of the OH ground state has been detected for the first time. The radial velocity of the feature, V_LSR = 3.6 km s−1, has a “blue” shift relative to the range of emission velocities in the main 1665- and 1667-MHz OH lines, which is 8–11 km s−1. This suggests a probable connection of the observed feature in the 1720-MHz line with the “blue” wing of the bipolar outflow observed in this region in the CO line. We have estimated the magnetic field strength for three features (0.90 and 0.8 mG for 1665 MHz and 0.25 mG for 1720 MHz) from the Zeeman splitting in the 1665- and 1720-MHz lines. No emission and (or) absorption has been detected in the other 1612-MHz satellite OH line. Three cycles of H₂O maser activity have been revealed. The variability is quasi-periodic in pattern. There is a general tendency for the maser activity to decrease. Some clusters of H2O maser spots can form organized structures, for example, chains and other forms.