The OH (1720 MHz) Supernova Remnant Masers in W44: MERLIN and VLBA Polarization Observations

Abstract

Full-polarization MERLIN and VLBA observations of the 1720-MHz maser emission from the OH molecule in the supernova remnant W44 are presented. Zeeman splitting has been directly resolved between right- and left-circularly polarized spectra indicating magnetic field strengths of B~0.50 mG. The position angle of the linear polarization is in good agreement with the orientation of the shocked gas at the supernova remnant/molecular cloud interface. Based on MERLIN data having a resolution of 200 milliarcseconds (mas) and VLBA data with a resolution of 15 mas, the masers are measured to have deconvolved angular sizes of 50 to 350 mas (150 to 1000 AU) with compact cores 20 mas (60 AU) in size, consistent with theoretical expectation and previous observations.

arXiv comment33 pages, 7 figures, 7 tables; accepted to ApJ

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Cited by in corpus (21)

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• A Masing Event in NGC6334I: Contemporaneous Flaring of Hydroxyl, Methanol and Water Masers
• Evidence for a neutral iron line generated by MeV protons from supernova remnants interacting with molecular clouds
• OH (1720 MHz) Masers: A Multiwavelength Study of the Interaction between the W51C Supernova Remnant and the W51B Star Forming Region
• Interstellar Plunging Waves: ALMA resolves the physical structure of non-stationary MHD shocks
• APEX observations of supernova remnants - I. Non-stationary MHD-shocks in W44
• On the gamma-ray emission of W44 and its surroundings
• Interaction between Cassiopeia A and Nearby Molecular Clouds
• A Very High Spectral Resolution Study of Ground-State OH Masers in W3(OH)
• A molecular outflow evidencing star formation activity in the vicinity of the HII region G034.8-0.7 and the SNR W44
• A Review of Maser Polarization and Magnetic Fields
• Magnetohydrodynamic Simulations of a Plunging Black Hole into a Molecular Cloud
• Modelling cosmic masers in C-type shock waves -- the coexistence of Class I CH3OH and 1720 MHz OH masers
• Interaction between the Supernova Remnant W44 and the Infrared Dark Cloud G034.77-00.55: shock induced star formation?
• Collisional Pumping of OH Masers near Supernova Remnants
• Collisional Pumping of H${}_2$O and CH${}_3$OH Masers in C-Type Shock Waves