EVN observations of 6.7 GHz methanol maser polarization in massive star-forming regions III. The flux-limited sample

Abstract

Theoretical simulations and observations at different angular resolutions have shown that magnetic fields have a central role in massive star formation. Like in low-mass star formation, the magnetic field in massive young stellar objects can either be oriented along the outflow axis or randomly. Measuring the magnetic field at milliarcsecond resolution (10-100 au) around a substantial number of massive young stellar objects permits determining with a high statistical significance whether the direction of the magnetic field is correlated with the orientation of the outflow axis or not. In late 2012, we started a large VLBI campaign with the European VLBI Network to measure the linearly and circularly polarized emission of 6.7 GHz methanol masers around a sample of massive star-forming regions. This paper focuses on the first seven observed sources, G24.78+0.08, G25.65+1.05, G29.86-0.04, G35.03+0.35, G37.43+1.51, G174.20-0.08, and G213.70-12.6. For all these sources, molecular outflows have been detected in the past. We detected a total of 176 methanol masing cloudlets toward the seven massive star-forming regions, 19% of which show linearly polarized emission. The methanol masers around the massive young stellar object MM1 in G174.20-0.08 show neither linearly nor circularly polarized emission. The linear polarization vectors are well ordered in all the other massive young stellar objects. We measured significant Zeeman splitting toward both A1 and A2 in G24.78+0.08, and toward G29.86-0.04 and G213.70-12.6. By considering all the 19 massive young stellar objects reported in the literature for which both the orientation of the magnetic field at milliarcsecond resolution and the orientation of outflow axes are known, we find evidence that the magnetic field (on scales 10-100 au) is preferentially oriented along the outflow axes.

17 pages, 10 figures, 9 tables, accepted by Astronomy & Astrophysics. arXiv admin note: text overlap with arXiv:1306.6335

References in corpus (15)

• Theory of Star Formation
• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• Magnetic Fields and Massive Star Formation
• The Fragmentation of Magnetized, Massive Star-Forming Cores with Radiative Feedback
• Trigonometric parallaxes of star forming regions in the Sagittarius spiral arm
• Infall of gas as the formation mechanism of stars up to 20 times more massive than the Sun
• Multiple Jets from the High-Mass (Proto)stellar Cluster AFGL5142
• Magnetic fields in massive star forming regions
• A new probe of magnetic fields during high-mass star formation: Zeeman splitting of 6.7 GHz methanol masers
• Methanol Maser Associated Outflows: Detection statistics and properties
• Time Variation in G24.78+0.08 A1: Evidence for an Accreting Hypercompact H II Region?
• Millimetre Continuum Observations of Southern Massive Star Formation Regions II. SCUBA observations of cold cores and the dust grain emissivity index $\beta$
• Associations of water and methanol masers at milli-arcsec angular resolution in two high-mass young stellar objects
• Molecular outflows around high-mass young stellar objects
• Submillimeter Array High-angular Resolution Observations of the Monoceros R2 Star Forming Cluster

Cited by in corpus (5)

• Review of Zeeman Effect Observations of Regions of Star Formation
• Protostellar Outflows at the EarliesT Stages (POETS). II. A possible radio synchrotron jet associated with the EGO G035.02+0.35
• VLA Survey of Dense Gas in Extended Green Objects: Prevalence of 25 GHz Methanol Masers
• EVN observations of 6.7 GHz methanol maser polarization in massive star-forming regions IV. Magnetic field strength limits and structure for 7 additional sources
• Methanol masers reveal the magnetic field of the high-mass protostar IRAS 18089-1732