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

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This paper presents a milliarcsecond-scale comparison of the polarised component-level v=1 J=1-0, v=2 J=1-0 and v=1 J=2-1 SiO maser emission toward the supergiant star VY CMa. These observations used the VLBA at {\lambda}=7mm and…

Solar and Stellar Astrophysics · Physics 2013-10-03 Laura Richter , Athol Kemball , Justin Jonas

This work presents a detailed study of the gas kinematics towards the "Hot Molecular Core" (HMC) G31.41+0.31 via multi-epoch VLBI observations of the H2O 22 GHz and CH3OH 6.7 GHz masers, and single-epoch VLBI of the OH 1.6 GHz masers. Water…

Solar and Stellar Astrophysics · Physics 2015-06-12 Luca Moscadelli , Jing Jing Li , Riccardo Cesaroni , Alberto Sanna , Ye Xu , Qizhou Zhang

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

Results of astrometric very long baseline interferometry (VLBI) observations towards an extreme OH/IR star candidate NSV17351 are presented. We used the VERA (VLBI Exploration of Radio Astrometry) VLBI array to observe 22\,GHz H$_2$O masers…

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 report phase-referencing VLBA observations of H2O masers near the star-forming region W3(OH) to measure their parallax and absolute proper motions. The measured annual parallax is 0.489 +/- 0.017 milli-arcseconds (2.04 +/- 0.07 kpc),…

We present five epochs of VLBI water maser observations around the massive protostar Cepheus A HW2 with 0.4 mas (0.3 AU) resolution. The main goal of these observations was to follow the evolution of the remarkable water maser…

Solar and Stellar Astrophysics · Physics 2015-05-19 J. M. Torrelles , N. A. Patel , S. Curiel , R. Estalella , J. F. Gomez , L. F. Rodriguez , J. Canto , G. Anglada , W. Vlemmings , G. Garay , A. Raga , P. T. P. Ho

We present the results of astrometic observations of H2O masers associated with the star forming region G192.16-3.84 with the VLBI Exploration of Radio Astrometry (VERA). The H2O masers seem to be associated with two young stellar objects…

Astrophysics of Galaxies · Physics 2015-05-30 Satoshi Shiozaki , Hiroshi Imai , Daniel Tafoya , Toshihiro Omodaka , Tomoya Hirota , Mareki Honma , Makoto Matsui , Yuji Ueno

The OH 1667 MHz maser in the circumstellar shell around the Mira variable U Herculis has been observed with the NRAO Very Long Baseline Array (VLBA) at 6 epochs, spread over 4 years. Using phase referencing techniques the position of the…

Astrophysics · Physics 2007-05-23 H. J. van Langevelde , W. Vlemmings , P. J. Diamond , A. Baudry , A. J. Beasley

We report the discovery of new, high-velocity narrow-line components of the OH megamaser in IRAS 20100-4156. Results from the Australian Square Kilometre Array Pathfinder (ASKAP)'s Boolardy Engineering Test Array (BETA) and the Australia…

New visible and K-band polarization measurements on stars surrounding molecular clouds in Orion A and stars in the BN vicinity are presented. Our results confirm that magnetic fields located inside the Orion A molecular clouds and in their…

Astrophysics of Galaxies · Physics 2015-05-30 Frédérick Poidevin , Pierre Bastien , Terry J. Jones

We present here a mid-infrared imaging survey of 26 sites of water maser emission. Observations were obtained at the InfraRed Telescope Facility 3-m telescope with the University of Florida mid-infrared imager/spectrometer OSCIR, and the…

Astrophysics · Physics 2009-11-10 J. M. De Buizer , J. T. Radomski , C. M. Telesco , R. K. Pina

We aim to detect the magnetic field and infer its properties around four AGB stars using H$_2$O maser observations. The sample we observed consists of the following sources: the semi-regular variable RT Vir and the Mira variables AP Lyn, IK…

Solar and Stellar Astrophysics · Physics 2015-06-15 M. L. Leal-Ferreira , W. H. T. Vlemmings , A. Kemball , N. Amiri

We report millimeter interferometric observations of polarized continuum and line emission from the massive star forming region G34.4. Polarized thermal dust emission at 3 mm wavelength and CO $J=1 \to 0$ line emission were observed using…

Astrophysics · Physics 2009-11-13 P. C. Cortes , R. M. Crutcher , D. Shepherd , L. Bronfman

General solutions of the maser polarization problem are presented for arbitrary absorption coefficients. The results are used to calculate polarization for masers permeated by magnetic fields with arbitrary values of \xB, the ratio of…

Astrophysics · Physics 2009-10-28 Moshe Elitzur

When observed in quiet regions close to the solar limb, many strong resonance lines show conspicuous linear polarization signals, produced by scattering processes, with extended wing lobes. Recent studies indicate that, contrary to what was…

Solar and Stellar Astrophysics · Physics 2022-01-12 Emilia Capozzi , Ernest Alsina Ballester , Luca Belluzzi , Javier Trujillo Bueno

We present observations of molecular gas made with the 15-m James Clark Maxwell Telescope toward the sites of OH(1720 MHz) masers in three supernova remnants: W28, W44 and 3C391. Maps made in the 12CO J=3-2 line reveal that the OH masers…

Astrophysics · Physics 2009-10-30 Dale A. Frail , George F. Mitchell

Most of PNe are not spherical. The loss of spherical symmetry occurs somewhere between the AGB and PN phase. The cause of this change of morphology is not yet well known, but magnetic fields are one of the possible agents. Its origin…

Solar and Stellar Astrophysics · Physics 2015-06-03 M. L. Leal-Ferreira , W. H. T. Vlemmings , P. J. Diamond , A. Kemball , N. Amiri , J. -F. Desmurs

A new class of OH (1720 MHz) masers unaccompanied by main-line transitions have recently been discovered (Frail, Goss and Slysh 1994). These masers lie at the interface between supernova remnants (SNRs) interacting with molecular clouds. We…

Astrophysics · Physics 2007-05-23 F. Yusef-Zadeh , D. A. Roberts , G. Bower , M. Wardle

We report on high spatial resolution observations, using the Australia Telescope Compact Array (ATCA), of ground-state OH masers. These observations were carried out toward 196 pointing centres previously identified in the Southern Parkes…