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Related papers: Total linear polarization in the OH maser W75N: VL…

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We present results of a high resolution survey of OH masers in Galactic Star Forming Regions in order to study the maser emission and establish a list of suitable candidates for higher resolution instruments follow up. We used the Very Long…

Astrophysics · Physics 2007-05-23 A. E. Ruiz-Velasco , V. Migenes , V. Slysh , I. E. Val'tts

We present the results of MERLIN polarization mapping of OH masers at 1665 and 1667 MHz towards the Cepheus A star-forming region. The maser emission is spread over a region of 6 arcsec by 10 arcsec, twice the extent previously detected. In…

Astrophysics · Physics 2009-11-11 A. Bartkiewicz , M. Szymczak , R. J. Cohen , A. M. S. Richards

The majority of the observed planetary nebulae exhibit elliptical or bipolar structures. Theoretical modeling has indicated that magnetically collimated jets may be responsible for the formation of the non-spherical planetary nebulae. The…

Solar and Stellar Astrophysics · Physics 2015-05-14 N. Amiri , W. H. T. Vlemmings , H. J. van Langevelde

We have identified and classified Zeeman pairs in the survey by Argon, Reid, & Menten of massive star-forming regions with 18 cm (2 Pi 3/2, J = 3/2) OH maser emission. We have found a total of more than 100 Zeeman pairs in more than 50…

Astrophysics · Physics 2009-11-10 Vincent L. Fish , Mark J. Reid , Alice L. Argon , Karl M. Menten

We present a parsec-scale image of the OH maser in the nucleus of the active galaxy IIIZw35, made using the Very Long Baseline Array at a wavelength of 18 cm. We detected two distinct components, with a projected separation of 50 pc (for…

Astrophysics · Physics 2016-08-30 A. S. Trotter , J. M. Moran , L. J. Greenhill , X. -W. Zheng , C. R. Gwinn

We report on the first space-VLBI observations of the OH masers in two main-line OH transitions at 1665 and 1667 MHz. The observations involved the space radio telescope on board the Japanese satellite HALCA and an array of ground radio…

Astrophysics · Physics 2007-05-23 V. I. Slysh , M. A. Voronkov , I. E. Val'tts , V. Migenes , K. M. Shibata , T. Umemoto

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 used the NRAO Very Long Baseline Array (VLBA) to image OH(1720 MHz) masers in the supernova remnants W28 and W44 at a resolution of 40 mas. We also used MERLIN to observe the same OH(1720 MHz) masers in W44 at a resolution of 290 x…

Astrophysics · Physics 2009-10-31 M. J. Claussen , W. M. Goss , D. A. Frail , K. Desai

We present high angular resolution observations of OH maser emission towards the high-mass star forming region IRAS 06056+2131. The observations were carried out using the UK radio interferometer array, Multi-Element Radio Linked…

Solar and Stellar Astrophysics · Physics 2021-01-19 Mohamed Said darwish , Anita M. S. Richards , Sandra Etoka , Khaled Edris , Somaya Saad , Mohamed Beheary , Gary Fullar

We present global VLBI observations of the first-excited state OH masers in the massive star-forming region Onsala 1 (ON 1). The 29 masers detected are nearly all from the 6035 MHz transition, and nearly all are identifiable as Zeeman pair…

Astrophysics of Galaxies · Physics 2010-04-23 Vincent L. Fish , Loránt O. Sjouwerman

The polarized emission of astrophysical masers, especially OH and methanol lines, is an effective tool to study the magnetic field in high-mass star-forming regions. The magnetic field strength measurement via the Zeeman effect of OH maser…

Astrophysics of Galaxies · Physics 2025-08-21 A. Kobak , G. Surcis , A. Bartkiewicz , W. H. T. Vlemmings , M. Szymczak

Context. Maser emission is a strong tool for studying high mass star forming regions and their evolutionary stages. OH masers in particular can trace the circumstellar material around protostars and determine their magnetic field strengths…

Astrophysics of Galaxies · Physics 2017-12-13 K. A. Edris , G. A. Fuller , S. Etoka , R. J. Cohen

NGC7538 is a complex massive star-forming region. The region is composed of several radio continuum sources, one of which is IRS1, a high-mass protostar, from which a 0.3 pc molecular bipolar outflow was detected. Several maser species have…

Solar and Stellar Astrophysics · Physics 2015-05-28 G. Surcis , W. H. T. Vlemmings , R. M. Torres , H. J. van Langevelde , B. Hutawarakorn Kramer

We present the first circular polarization measurements of circumstellar H2O masers. Previously the magnetic field in circumstellar envelopes has been estimated using polarization observations of SiO and OH masers. SiO masers are probes of…

Astrophysics · Physics 2009-11-06 W. Vlemmings , P. J. Diamond , H. J. van Langevelde

Results of observations of the maser sources toward the W33C region (G12.8-0.2) carried out on the 22-m radio telescope of the Pushchino Radio Astronomy Observatory in the 1.35-cm H2O line and on the Large radio telescope in Nancay (France)…

Astrophysics of Galaxies · Physics 2015-06-11 P. Colom , E. E. Lekht , M. I. Pashchenko , G. M. Rudnitskij

Using the Very Long Baseline Array (VLBA) we performed a high resolution OH maser survey in Galactic star-forming regions (SFRs). We observed all the ground state spectral lines: the main lines at 1665 and 1667 MHz and the satellite lines…

Solar and Stellar Astrophysics · Physics 2016-03-28 A. E. Ruiz-Velasco , D. Felli , V. Migenes , B. K. Wiggins

Although the role of magnetic fields in launching molecular outflows in massive YSOs has been convincingly demonstrated by theoretical arguments, observationally, the alignment of the magnetic field lines with the molecular outflows is…

Astrophysics of Galaxies · Physics 2022-02-02 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , B. Hutawarakorn Kramer , A. Bartkiewicz

We use unpublished and published VLBI results to investigate the geometry and the statistical properties of the velocity field traced by H2O masers in five galactic regions of star formation -- Sgr B2(M), W49N, W51(MAIN), W51N, and W3(OH).…

Astrophysics · Physics 2009-11-07 V. Strelnitski , J. Alexander , S. Gezari , B. P. Holder , J. M. Moran , M. J. Reid

We present circular polarization measurements of circumstellar H_2O masers. The circular polarization detected in the (6_{16}-5_{23}) rotational transition of the H_{2}O maser can be attributed to Zeeman splitting in the intermediate…

Astrophysics · Physics 2009-11-07 W. H. T. Vlemmings , P. J. Diamond , H. J. van Langevelde

MHD simulations show that the magnetic field can drive molecular outflows during the formation of massive protostars. The best probe to observationally measure both the morphology and the strength of this magnetic field at scales of 10-100…

Solar and Stellar Astrophysics · Physics 2019-03-20 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , B. Hutawarakorn Kramer , A. Bartkiewicz