Magnetic field measurements at milliarcsecond resolution around massive young stellar objects

Magnetic fields have only recently been included in theoretical simulations of high-mass star formation. The simulations show that magnetic fields can play a crucial role not only in the formation and dynamics of molecular outflows, but also in the evolution of circumstellar disks. Therefore, new measurements of magnetic fields at milliarcsecond resolution close to massive young stellar objects (YSOs) are fundamental for providing new input for numerical simulations and for understanding the formation process of massive stars. The polarized emission of 6.7 GHz CH3OH masers allows us to investigate the magnetic field close to the massive YSO where the outflows and disks are formed. Recently, we have detected with the EVN CH3OH maser polarized emission towards 10 massive YSOs. From a first statistical analysis we have found evidence that magnetic fields are primarily oriented along the molecular outflows. To improve our statistics we are carrying on a large observational EVN campaign for a total of 19 sources, the preliminary results of the first seven sources are presented in this contribution. Furthermore, we also describe our efforts to estimate the Lande' g-factors of the CH3OH maser transition to determine the magnetic field strength from our Zeeman-splitting measurements.Comment: Accepted for publication in the proceeding of the "12th European VLBI Network Symposium and Users Meeting", eds Tarchi et al. PoS(EVN 2014)04

A new sample of OH/IR stars in the Galactic center

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Stellar positions from SiO masers in the Galactic center

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Circular polarization of circumstellar water masers around S Per

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The nature of OH/IR stars in the galactic centre

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Anomalously excited OH and the competition between maser transitions toward Centaurus A

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Envelope structure on 700 AU scales and the molecular outows of low - mass young stellar objects

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The magnetic field in the star-forming region Cepheus A. from H_2O maser polarization observations

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SN 2007gr: a Normal Type Ic Supernova with a Mildly Relativistic Radio Jet?

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Sub - arcsec imaging at 267 GHz of a young binary system: detection of a dust disk of radius less than 70 AU around T Tauri N

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