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Context. Class II methanol masers at 6.7 and 12.2 GHz occur close to high-mass young stellar objects (HMYSOs). When they are observed simultaneously, such studies may contribute to refining the characterisation of local physical conditions.…

Astrophysics of Galaxies · Physics 2021-04-28 M. Durjasz , M. Szymczak , P. Wolak , A. Bartkiewicz

Results of a survey of Galactic star-forming regions in the lines of methanol 8_{-1}-7_0E at 229.8 GHz, 3_{-2}-4_{-1}E at 230.0 GHz, 0_0-1_{-1}E at 108.9 GHz, and a series of methanol lines J_1-J_0E near 165 GHz are presented. Two masers,…

Astrophysics · Physics 2007-05-23 S. V. Kalenskii , V. I. Slysh , I. E. Val'tts

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 have used the Australia Telescope National Facility Mopra 22-m antenna to search for 37.7-GHz (7(-2) - 8(-1}E) methanol masers towards a sample of thirty six class II methanol masers. The target sources are the most luminous class II…

Astrophysics of Galaxies · Physics 2015-06-12 S. P. Ellingsen , S. L. Breen , M. A. Voronkov , J. R. Dawson

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 Swedish ESO Submillimetre Telescope (SEST) to search for new class II methanol maser transitions towards the southern source G345.01+1.79. Over a period of 5 days we observed 11 known or predicted class II methanol maser…

Astrophysics of Galaxies · Physics 2015-06-11 S. P. Ellingsen , A. M. Sobolev , D. M. Cragg , P. D. Godfrey

We present definitive detection statistics for 12.2 GHz methanol masers towards a complete sample of 6.7 GHz methanol masers detected in the Methanol Multibeam survey south of declination -20 degrees. In total, we detect 250 12.2 GHz…

Astrophysics of Galaxies · Physics 2015-05-27 Shari Breen , Simon Ellingsen , James Caswell , James Green , Gary Fuller , Maxim Voronkov , Lyshia Quinn , Adam Avison

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

The methanol molecule CH3OH has a complex microwave spectrum with a large number of very strong lines. This spectrum includes purely rotational transitions as well as transitions with contributions of the internal degree of freedom…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-12 S. A. Levshakov , M. G. Kozlov , D. Reimers

The Australia Telescope Compact Array (ATCA) has been used for high angular resolution imaging of 71 southern class I methanol maser sources quasi-simultaneously at 36 and 44 GHz. The data reveal a high level of morphological and…

Astrophysics of Galaxies · Physics 2015-06-18 M. A. Voronkov , J. L. Caswell , S. P. Ellingsen , J. A. Green , S. L. Breen

Class I methanol masers are collisionally pumped and are generally correlated with outflows in star forming sites in the Galaxy. Using the VLA in its A-array configuration, we present a spectral line survey to identify methanol…

Astrophysics of Galaxies · Physics 2016-12-14 W. Cotton , F. Yusef-Zadeh

We use a Fourier transform spectrometer based on a difference frequency generation optical frequency comb to measure high-resolution, low-pressure, room-temperature spectra of methane in the 1250 - 1380 cm$^{-1}$ range. From these spectra,…

We have performed a molecular line search toward the flaring 6.7-GHz masers G24.33+0.13 and G359.62-0.24 using the Australia Telescope Compact Array. We present spectra of the 6.7-GHz class~II methanol and 22.2-GHz water masers toward these…

We report the first observations in a rare family of class II methanol maser transitions in both CH$_3$OH and $^{13}$CH$_3$OH toward three southern high-mass star formation regions, along with the first maser detected in the $^{13}$CH$_3$OH…

We report the detection with the ATCA of 6.7 GHz methanol emission towards OMC-1. The source has a size between 40'' and 90'', is located to the south-east of Ori-KL and may coincide in position with the 25 GHz masers. The source may be an…

Astrophysics · Physics 2009-11-10 M. A. Voronkov , A. M. Sobolev , S. P. Ellingsen , A. B. Ostrovskii , A. V. Alakoz

We report the results of a search for class II methanol masers at 37.7, 38.3 and 38.5 GHz towards a sample of 70 high-mass star formation regions. We primarily searched towards regions known to show emission either from the 107 GHz class II…

Astrophysics of Galaxies · Physics 2015-05-30 S. P. Ellingsen , S. L. Breen , A. M. Sobolev , M. A. Voronkov , J. L. Caswell , N. Lo

Recent studies have shown that 6.7 GHz methanol maser flares can be a powerful tool for verifying the mechanisms of maser production and even the specific signatures of accretion rate changes in the early stages of high-mass star formation.…

We show that in many methanol maser sources the masers are located in lines, with a velocity gradient along them which suggests that the masers are situated in edge-on circumstellar, or protoplanetary, disks. We present VLBI observations of…

The Australia Telescope Compact Array (ATCA) has been used to image class I methanol masers at 9.9, 25 (a series from J=2 to J=9), 84, 95 and 104 GHz located in the vicinity of IRAS 16547-4247 (G343.12-0.06), a luminous young stellar object…

Methanol masers at 6.7~GHz are well-known signposts of high-mass star-forming regions. [...] We aim to understand the origin of the ring-like structures outlined by methanol maser emission in a number of sources. This emission could be, a…

Astrophysics of Galaxies · Physics 2024-06-19 A. Bartkiewicz , A. Sanna , M. Szymczak , L. Moscadelli , H. J. van Langevelde , P. Wolak , A. Kobak , M. Durjasz