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Methanol masers can provide valuable insight into the processes involved in high-mass star formation, however the local environment in which they form is still unclear. Four primary, yet conflicting, models have emerged to explain the…

Astrophysics of Galaxies · Physics 2013-06-25 Richard Dodson , Charles Moriarty

We have used the Australian Long Baseline Array (LBA) to produce milliarcsecond images of five sites of methanol maser emission at 6.7 GHz. These are all sites that have linear morphologies at arcsecond resolutions, which have been…

Astrophysics · Physics 2009-11-10 R. Dodson , R. Ojha , S. P. Ellingsen

We investigate which structures the 6.7 GHz methanol masers trace in the environment of high-mass protostar candidates by observing a homogenous sample of methanol masers selected from Torun surveys. We also probed their origins by looking…

Astrophysics of Galaxies · Physics 2015-05-13 A. Bartkiewicz , M. Szymczak , H. J. van Langevelde , A. M. S. Richards , Y. M. Pihlstrom

Very long baseline interferometry (VLBI) monitoring of the 6.7 GHz methanol maser allows us to measure the internal proper motions of the maser spots and therefore study the gas motion around high-mass young stellar objects. To this end, we…

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…

Solar and Stellar Astrophysics · Physics 2015-06-17 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , B. Hutawarakorn Kramer , A. Bartkiewicz , M. G. Blasi

We have observed 13 methanol maser sources associated with massive star-forming regions; W3(OH), Mon R2, S 255, W 33A, IRAS 18151-1208, G 24.78+0.08, G 29.95-0.02, IRAS 18556+0136, W 48, OH 43.8-0.1, ON 1, Cep A and NGC 7538 at 6.7 GHz…

The role of magnetic fields during the protostellar phase of high-mass star-formation is a debated topic. In particular, it is still unclear how magnetic fields influence the formation and dynamic of disks and outflows. Most current…

Solar and Stellar Astrophysics · Physics 2015-05-14 G. Surcis , W. H. T. Vlemmings , R. Dodson , H. J. van Langevelde

Class I methanol masers are found to be good tracers of the interaction between outflows from massive young stellar objects with their surrounding media. Although polarization observations of Class II methanol masers have been able to…

Astrophysics of Galaxies · Physics 2017-01-16 Ji-hyun Kang , Do-Young Byun , Kee-Tae Kim , Jongsoo Kim , Aran Lyo , W. H. T. Vlemmings

We present a survey of the polarization properties of mm-wavelength methanol masers, comprising both classes, and transitions from 84.5 to 157.0 GHz. Linear polarization is found in more than half of the observed objects, and circular…

Astrophysics · Physics 2009-11-10 Helmut Wiesemeyer , Clemens Thum , Malcolm Walmsley

The Australia Telescope Compact Array (ATCA) has been used to make the first full polarization observations of 6.7 GHz methanol masers. Linear polarization was detected towards all four sources observed, at levels between a few and 10%,…

Astrophysics · Physics 2007-05-23 S. P. Ellingsen

Recent studies have shown that 6.7 GHz methanol maser flares can be a powerful tool for verifying the mechanisms of maser production and even the specific signatures of accretion rate changes in the early stages of high-mass star formation.…

We present the first 6.7 GHz methanol maser linear polarization map of the extended filamentary maser structure around the compact HII region W3(OH). The methanol masers show linear polarization up to 8 per cent and the polarization angles…

Astrophysics · Physics 2009-11-11 W. H. T. Vlemmings , L. Harvey-Smith , R. J. Cohen

Methanol masers at 6.7 GHz are well known tracers of high-mass star-forming regions. However, their origin is still not clearly understood. We aimed to determine the morphology and velocity structure for a large sample of the maser emission…

Astrophysics of Galaxies · Physics 2016-03-02 Anna Bartkiewicz , Marian Szymczak , Huib J. van Langevelde

22 GHz water and 6.7 GHz methanol masers are usually thought as signposts of early stages of high-mass star formation but little is known about their associations and the physical environments they occur in. The aim was to obtain accurate…

Astrophysics of Galaxies · Physics 2015-05-19 A. Bartkiewicz , M. Szymczak , Y. M. Pihlström , H. J. van Langevelde , A. Brunthaler , M. J. Reid

We present accurate absolute astrometry of 6.7 GHz methanol masers detected in the Arecibo Methanol Maser Galactic Plane Survey using MERLIN and the Expanded Very Large Array (EVLA). We estimate the absolute astrometry to be accurate to…

Solar and Stellar Astrophysics · Physics 2015-05-27 J. D. Pandian , E. Momjian , Y. Xu , K. M. Menten , P. F. Goldsmith

The European VLBI Network (EVN) has been used to make phase referenced, wide-field (several arcminute) spectral line observations of the 6.7-GHz methanol maser emission towards W51. In the W51main region, the bulk of the methanol is offset…

Astrophysics · Physics 2009-11-10 C. J. Phillips , H. J. van Langevelde

Emission from the 6.7 GHz methanol maser transition is very strong, is relatively stable, has small internal motions, and is observed toward numerous massive star-forming regions in the Galaxy. Our goal is to perform high-precision…

Astrophysics of Galaxies · Physics 2015-05-14 K. L. J. Rygl , A. Brunthaler , M. J. Reid , K. M. Menten , H. J. van Langevelde , Y. Xu

Spectra of 6.7 GHz methanol masers from 21 pointings of known star-forming regions are reported. The C-band observations, using the Green Bank Telescope in full Stokes mode, have measured how polarization properties vary across the maser…

Astrophysics of Galaxies · Physics 2026-05-19 Paul Fallon , Derck P. Smits

We present the second portion of a catalogue of 12.2-GHz methanol masers detected towards 6.7-GHz methanol masers observed in the unbiased Methanol Multibeam (MMB) Survey. Using the Parkes radio telescope we have targeted all 207 6.7-GHz…

Astrophysics of Galaxies · Physics 2015-06-05 Shari Breen , Simon Ellingsen , James Caswell , James Green , Maxim Voronkov , Gary Fuller , Lyshia Quinn , Adam Avison

MERLIN observations of 6.668-GHz methanol and both 6.031- and 6.035-GHz hydroxyl (OH) emission from the massive star-formation region ON1 are presented. These are the first methanol observations made in full polarization using 5 antennas of…

Astrophysics · Physics 2009-11-13 J. A. Green , A. M. S. Richards , W. H. T. Vlemmings , P. Diamond , R. J. Cohen
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