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Discovery of periodic maser emission was an unexpected result from monitoring observations of methanol transitions in high-mass young stellar objects. We report on the detection of five new periodic sources from a monitoring program with…

Solar and Stellar Astrophysics · Physics 2020-01-08 Mateusz Olech , Marian Szymczak , Paweł Wolak , Rafał Sarniak , Anna Bartkiewicz

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

We report dual-frequency very long baseline interferometry (VLBI) observations at 22 and 43 GHz toward the nucleus of a nearby radio galaxy NGC 4261. In particular, we present a VLBI image of the 22 GHz H2O maser line and its location in…

Astrophysics of Galaxies · Physics 2023-05-31 Satoko Sawada-Satoh , Nozomu Kawakatu , Kotaro Niinuma , Seiji Kameno

We analyzed the 3-mm wavelength spectral line survey of 408 ATLASGAL clumps observed with the IRAM 30m-telescope, focusing on the class I methanol masers with frequencies near 84, 95 and 104.3 GHz. We detect narrow, maser-like features…

Astrophysics of Galaxies · Physics 2023-07-12 W. Yang , Y. Gong , K. M. Menten , J. S. Urquhart , C. Henkel , F. Wyrowski , T. Csengeri , S. P. Ellingsen , A. R. Bemis , J. Jang

We report results of EVN interferometric study of two star-forming regions L1206 and GL2789 in the brightest methanol maser line at 6.7 GHz. Using measured absolute positions both methanol masers were identified with protostars which are…

Astrophysics · Physics 2007-05-23 M. A. Voronkov , V. I. Slysh

We present the first VLBI observations of a Galactic water maser (in Chepeus A) made with a very long baseline interferometric array involving the RadioAstron Earth-orbiting satellite station as one of its elements. We detected two distinct…

Astrophysics of Galaxies · Physics 2018-04-11 A. M. Sobolev , J. M. Moran , M. D. Gray , A. Alakoz , H. Imai , W. A. Baan , A. M. Tolmachev , V. A. Samodurov , D. A. Ladeyshchikov

We present a simultaneous single-dish survey of 22 GHz water maser and 44 GHz and 95 GHz class I methanol masers toward 77 6.7 GHz class II methanol maser sources, which were selected from the Arecibo methanol maser Galactic plane survey…

Solar and Stellar Astrophysics · Physics 2015-11-18 Hyunwoo Kang , Kee-Tae Kim , Do-Young Byun , Seokho Lee , Yong-Sun Park

We used the Very Long Baseline Array (VLBA) and the European VLBI Network (EVN) to perform phase-referenced VLBI observations of the three most powerful maser transitions associated with the high-mass star-forming region G28.87+0.07: the…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. J. Li , L. Moscadelli , R. Cesaroni , R. S. Furuya , Y. Xu , T. Usuda , K. M. Menten , M. Pestalozzi , D. Elia , E. Schisano

This work presents a study of the milliarcsecond structure of the 6.7 GHz methanol masers at high-velocity resolution (0.09 km s^(-1)) in four high-mass star-forming regions: G16.59-0.05, G23.01-0.41, IRAS20126+4104, and AFGL5142. We…

Solar and Stellar Astrophysics · Physics 2015-05-30 Luca Moscadelli , Alberto Sanna , Ciriaco Goddi

We investigate class II methanol masers and the environment in which they form with the Long Baseline Array (LBA). Using full polarisation VLBI, we're able to measure the magnetic field directions so as to distinguish between the two main…

Astrophysics · Physics 2009-11-13 R. Dodson

Methanol masers at 6.7 GHz have been found exclusively towards high-mass star forming regions. Recently, some Class 0 protostars have been found to display conditions similar to what are found in hot cores that are associated with massive…

Astrophysics · Physics 2009-11-13 J. D. Pandian , S. Leurini , K. M. Menten , A. Belloche , P. F. Goldsmith

VLBA and EVN radio observations of H2O masers at 22 GHz and methanol masers at 6.7 GHz have been used to obtain images of the maser spots in the infrared object GL2789, which is associated with the young stellar object V645Cyg. The position…

Astrophysics · Physics 2009-11-07 V. I. Slysh , M. A. Voronkov , I. E. Val'tts , V. Migenes

We review properties of all known collisionally pumped (class I) methanol maser series based on observations with the Australia Telescope Compact Array (ATCA) and the Mopra radio telescope. Masers at 36, 84, 44 and 95 GHz are most…

Astrophysics of Galaxies · Physics 2015-06-04 M. A. Voronkov , J. L. Caswell , S. P. Ellingsen , S. L. Breen , T. R. Britton , J. A. Green , A. M. Sobolev , A. J. Walsh

We present the first EVN parallax measurements of 6.7 GHz methanol masers in star forming regions of the Galaxy. The 6.7 GHz methanol maser transition is a very valuable astrometric tool, for its large stability and confined velocity…

Astrophysics · Physics 2008-12-09 K. L. J. Rygl , A. Brunthaler , K. M. Menten , M. J. Reid , H. J. van Langevelde

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 report detection of moderate to high-mass star formation in an infrared dark cloud (G11.11-0.12) where we discovered class II methanol and water maser emissions at 6.7 GHz and 22.2 GHz, respectively. We also observed the object in…

Astrophysics · Physics 2009-11-13 Thushara Pillai , Friedrich Wyrowski , Karl M. Menten , Endrik Kr"ugel

We report simultaneous single-dish surveys of 22 GHz H2O and 44 and 95 GHz class I CH3OH masers toward 299 Red MSX Sources in the protostellar stage. The detection rates are 45% at 22 GHz, 28% at 44 GHz, and 23% at 95 GHz. There are 15, 53,…

Astrophysics of Galaxies · Physics 2018-05-23 Chang-Hee Kim , Kee-Tae Kim , Yong-Sun Park

We detail interferometric observations of 44GHz class I methanol masers detected by MALT-45 (a 7mm unbiased auto-correlated spectral-line Galactic-plane survey) using the Australia Telescope Compact Array. We detect 238 maser spots across…

Aims. We report the discovery of periodic maser variability of an unusual pattern in the high-mass young stellar object G26.598-0.024. Methods. A ten-year monitoring of the 6.7 GHz methanol maser was carried out with the Torun 32 m radio…

Astrophysics of Galaxies · Physics 2025-08-14 P. Wolak , M. Szymczak , A. Kobak , A. Varma , A. Bartkiewicz , J. O. Chibueze , B. Stecklum , C. J. Ugwu

We have used the Australia Telescope Compact Array (ATCA) to undertake the first high angular resolution observations of 37.7-GHz ($7_{-2} - 8_{-1}E$) methanol masers towards a sample of eleven high-mass star formation regions which host…

Astrophysics of Galaxies · Physics 2018-08-15 Simon Ellingsen , Maxim Voronkov , Shari Breen , Jim Caswell , Andrej Sobolev