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

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We report high angular resolution (3") Submillimeter Array (SMA) observations of the molecular cloud associated with the Ultra-Compact HII region G5.89-0.39. Imaged dust continuum emission at 870 micron reveals significant linear…

Magnetic fields have only recently been included in theoretical simulations of high-mass star formation. The simulations show that magnetic fields play an important role in the formation and dynamics of molecular outflows. Masers, in…

Solar and Stellar Astrophysics · Physics 2015-06-16 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , B. Hutawarakorn Kramer , L. H. Quiroga-Nunez

The OH main line masers in circumstellar shells were observed with astrometric VLBI in order to accurately determine the position of the star, as well as its motion, including the parallax. Results are presented on 4 Mira stars monitored…

Astrophysics · Physics 2007-05-23 Wouter Vlemmings , Huib Jan van Langevelde , Phil Diamond

We present phase-referenced VLBI results on the radio continuum and the OH 18 cm megamaser emission from the Ultra-Luminous Infrared Galaxy, IRAS 17208--0014. The observations were carried out at 1599 MHz using the Very Long Baseline Array,…

Astrophysics · Physics 2008-11-26 E. Momjian , J. D. Romney , C. L. Carilli , T. H. Troland

We have carried out ALMA observations of the massive star-forming region W75N(B), which contains the massive protostars VLA1, VLA2, and VLA3. Particularly, VLA2 is an enigmatic protostar associated with a wind-driven H$_2$O maser shell,…

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

We present the results of multi-epoch VERA observations of W49N - OH43.8-0.1 water maser pair. Based on the dual-beam VLBI observation with VERA, we successfully obtained the phase-referenced maps of OH43.8-0.1 with respect to the W49N…

Astrophysics · Physics 2007-05-23 Mareki Honma

The present paper focuses on the high-mass star-forming region G23.01-0.41. Methods: Using the VLBA and the EVN arrays, we conducted phase-referenced observations of the three most powerful maser species in G23.01-0.41: H2O at 22.2 GHz (4…

Astrophysics of Galaxies · Physics 2015-05-18 A. Sanna , L. Moscadelli , R. Cesaroni , A. Tarchi , R. S. Furuya , C. Goddi

Through polarization observations, circumstellar masers are excellent probes of the magnetic field in the envelopes of late-type stars. Whereas observations of the polarization of the SiO masers close to the star and on the OH masers much…

Astrophysics · Physics 2009-11-10 W. H. T. Vlemmings , H. J. van Langevelde , P. J. Diamond

We have made multi-epoch VLBI observations of H2O maser emission in the massive star forming region IRAS 06061+2151 with the Japanese VLBI network (JVN) from 2005 May to 2007 October. The detected maser features are distributed within an…

Using the Very Large Array (VLA), we observed all three of the 6-cm lines of the doublet Pi 1/2, J=1/2 state of OH with sub-arcsecond resolution (about 0.4 arcsec) in W49A. While the spatial distribution and the range in velocities of the…

Astrophysics · Physics 2009-09-29 Patrick Palmer , W. M. Goss

Despite first being detected in the 1970s, surprisingly little is known about the OH main line maser population in the nearby starburst galaxy M82. Sometimes referred to as 'kilomasers', they have isotropic luminosities intermediate between…

We present a survey in the 6_{16}-5_{23} rotational water transition toward 33 galactic ultracompact HII regions. Maser emission is detected toward 18 of these sources; two are new detections. High quality spectra are provided for all 18…

Astrophysics · Physics 2008-11-26 S. Kurtz , P. Hofner

We present Very Long Baseline Interferometry (VLBI) observations of 22 GHz H$_2$O masers in the high-mass star-forming region of \objectname{W75N}, carried out with VLBI Exploration of Radio Astrometry (VERA) for three-epochs in 2007 with…

We present a survey of OH maser emission towards a sample of high mass protostellar objects made using the Nancay and GBT telescopes.OH maser emission was detected towards 63 objects with 36 new detections. There are 56 star-forming regions…

Astrophysics · Physics 2009-11-13 K. A. Edris , G. A. Fuller , R. J . Cohen

We observed v=1, J=1-0 43-GHz SiO maser emission toward the Mira variable IK Tauri (IK Tau) using the Very Long Baseline Array (VLBA). The images resulting from these observations show that SiO masers form a highly elliptical ring of…

Astrophysics · Physics 2009-11-10 D. A. Boboltz , P. J. Diamond

MERLIN and VLBA observations of the 1720 MHz maser emission from the OH molecule in the supernova remnant IC443 are presented. Based on MERLIN data with a resolution of 160 mas, the deconvolved sizes of the maser sources are in the range 90…

Astrophysics · Physics 2009-11-07 Ian M. Hoffman , W. M. Goss , C. L. Brogan , M. J Claussen , A. M. S. Richards

OH 1612 and 1667 MHz masers from the well known object OH127.8+0.0 were mon- itored in full-polarization mode over a period of 6.5 years and mapped with MERLIN at one epoch. The OH variability pattern of the star is typical of extremely…

Astrophysics of Galaxies · Physics 2013-02-11 P. Wolak , M. Szymczak , E. Gerard

(Abridged) The goal of this work is to investigate if SiO, H2O and HCN maser emission within the ALMA frequency range can be detected with observable levels of fractional linear polarization in the regime where the Zeeman frequency (gOmega)…

Solar and Stellar Astrophysics · Physics 2015-06-12 A. F. Pérez-Sánchez , W. H. T. Vlemmings

We present VLBA observations of the ground-state hydroxyl masers in W3(OH) at 0.02 km s-1 spectral resolution. Over 250 masers are detected, including 56 Zeeman pairs. Lineshapes are predominantly Gaussian or combinations of several…

Astrophysics · Physics 2008-11-26 Vincent L. Fish , Walter F. Brisken , Loránt O. Sjouwerman
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