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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

The 22.2 GHz water masers are often associated with the 6.7 GHz methanol masers but owing to the different excitation conditions they likely probe independent spatial and kinematic regions around the powering young massive star. We compared…

Astrophysics of Galaxies · Physics 2015-06-04 Anna Bartkiewicz , Marian Szymczak , Huib Jan van Langevelde

We present the results of a high angular resolution Very Large Array (VLA) Class I 44 GHz and Class II 6.7 GHz methanol maser survey of a sample of ~20 massive young stellar object (MYSO) outflow candidates selected on the basis of extended…

Solar and Stellar Astrophysics · Physics 2009-09-28 C. J. Cyganowski , C. L. Brogan , T. R. Hunter , E. Churchwell

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…

We have conducted a sensitive water maser search with the ATCA towards 267 1.2-mm dust clumps presented in the literature. We combine our new observations with previous water maser observations to extend our sample to 294 1.2-mm dust…

Astrophysics of Galaxies · Physics 2015-05-28 Shari Breen , Simon Ellingsen

The 6.7~GHz methanol maser transition is exclusively associated with young, high-mass stars and represents a potential target for astrometric studies, including accurate determination of their distance through trigonometric parallax…

Astrophysics of Galaxies · Physics 2025-10-21 Lucas J. Hyland , Simon P. Ellingsen , Mark J. Reid

Context: Periodicity in 6.7 GHz methanol maser sources is a rare phenomenon that was discovered during long-term monitoring programmes. Understanding the underlying processes that lead to periodic variability might provide insights into the…

Astrophysics of Galaxies · Physics 2022-05-25 Mateusz Olech , Michał Durjasz , Marian Szymczak , Anna Bartkiewicz

We report on the detection of 44 GHz Class I methanol (CH3OH) maser emission in the SgrA complex with the Expanded Very Large Array (EVLA). These EVLA observations show that the SgrA complex harbors at least four different tracers of…

Astrophysics of Galaxies · Physics 2015-05-28 Y. M. Pihlström , L. O. Sjouwerman , V. L. Fish

The aim of this study is to investigate the distribution and excitation of the methanol gas around Cep A and to describe the physical conditions of the region. In addition the large scale abundance distribution is determined in order to…

We present milliarcsecond resolution images of the 6.7 and 12.2 GHz methanol maser emission associated with the well-known star formation region NGC 6334F. The images agree well with previous lower resolution observations, but detect…

We have used the University of Tasmania Mt Pleasant 26m radio telescope to investigate the polarisation characteristics of a sample of strong 6.7 GHz methanol masers, the first spectral line polarisation observations to be undertaken with…

Astrophysics of Galaxies · Physics 2015-05-30 P. D. Stack , S. P. Ellingsen

We have conducted the first parallax and proper motion measurements of 6.7 GHz methanol maser emission using the Australian Long Baseline Array (LBA). The parallax of G339.884$-$1.259 measured from five epochs of observations is 0.48$\pm…

The ATCA, MERLIN and VLA interferometers were used to measure the absolute positions of 35 6.7 GHz methanol masers to subarcsecond or higher accuracy. Our measurements represent essential preparatory data for Very Long Baseline…

Astrophysics of Galaxies · Physics 2015-05-14 Y. Xu , M. A. Voronkov , J. D. Pandian , J. J. Li , A. M. Sobolev , A. Brunthaler , B. Ritter , K. M. Menten

Aims. We aimed at investigating the structure and kinematics of the gaseous disk and outflows around the massive YSO S255 NIRS3 in the S255IR-SMA1 dense clump. Methods. Observations of the S255IR region were carried out with ALMA at two…

Astrophysics of Galaxies · Physics 2017-10-11 I. Zinchenko , S. -Y. Liu , Y. -N. Su , A. M. Sobolev

Periodic flares of maser emission are thought to be induced either by variations of the seed photon flux in young binary systems or the pump rate regulated by stellar and accretion luminosities. We seek to study the variability of four…

Solar and Stellar Astrophysics · Physics 2020-02-05 Mateusz Olech , Marian Szymczak , Paweł Wolak , Eric Gérard , Anna Bartkiewicz

We present results of the investigations of the properties of the methanol $J_1 - J_0$ A$^{-+}$ line series motivated by the recent serendipitous detection of the maser emission in the $14_1 - 14_0$ A$^{-+}$ line at 349~GHz in S255IR-SMA1…

Astrophysics of Galaxies · Physics 2022-03-30 Svetlana V. Salii , Igor I. Zinchenko , Sheng-Yuan Liu , Andrej M. Sobolev , Artis Aberfelds , Yu-Nung Su

We report the discovery of the Zeeman effect in the 44 GHz Class I methanol maser line. The observations were carried out with 22 antennas of the EVLA toward a star forming region in OMC-2. Based on our adopted Zeeman splitting factor of z…

Astrophysics of Galaxies · Physics 2015-05-27 A. P. Sarma , E. Momjian

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

Class I methanol masers are believed to be produced in the shock-excited environment around star-forming regions. Many authors have argued that the appearance of various subsets of class I masers may be indicative of specific evolutionary…

We present a study of signatures of on-going star formation in a sample of protostellar objects with enhanced 4.5 {\mu}m emission ('green' sources) near the Galactic center. To understand how star formation in the Galactic center region…

Astrophysics of Galaxies · Physics 2015-05-27 Edward T. Chambers , Farhad Yusef-Zadeh , Doug Roberts