Magnetic fields in methanol maser condensations based on data for related regions. Seven sources: Observational parameters

• Published in: Astronomy reports 2013-12, Vol.57 (12), p.889-903
• Main Authors: Bayandina, O. S., Alakoz, A. V., Val’tts, I. E.
• Format: Article
• Language: English
• Subjects: Astronomy; Condensing; Emission analysis; Emissions; Linear polarization; Magnetic fields; Masers; Methanol; Methyl alcohol; Observations and Techniques; Physics; Physics and Astronomy; Polarization; Stars & galaxies; Stokes parameters; Studies
• ISSN: 1063-7729; 1562-6881
• DOI: 10.1134/S1063772913120019

Results of polarization observations of gas-dust condensations obtained on the Nançay radio telescope in the 1665 and 1667 MHz OH lines in all four Stokes parameters are reported. Seven OH maser sources associated with methanol masers were selected for this study. The goal was to estimate the magnetic fields in methanol condensations from the Zeeman splitting of OH maser lines associated with the methanol masers. The Gaussian parameters of features in the OH spectra are presented, and their polarization parameters are estimated: the degree of circular polarization m C , flux density in linear polarization p , and degree of linear polarization m L . The magnetic field intensity B has been estimated from the Zeeman splitting of the OH lines and approximation of the Stokes parameter V from the derivative of Stokes parameter I . B varies from ≤0.5 to 1.4 mG for different sources. The association of OH masers with methanol emission has been analyzed; the magnetic fields of OH masers in interstellar condensations associated with Class I methanol masers can be determined more reliably than the fields in interstellar condensations with OH masers associated with Class II methanol emission, and have higher values. The sizes of the studied regions suggest they may be bound structures such as Bok globules, small IRDC clouds, or protoplanetary disks.