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The first high-resolution (5 mas) VLBI observations of 6.7-GHz methanol masers in DR21(OH)N, a candidate circumstellar disc around a very young massive star, are presented. Previous observations of these masers at 50 mas angular resolution…

Astrophysics · Physics 2009-11-13 Lisa Harvey-Smith , Rebeca Soria-Ruiz

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 have used the Australia Telescope Compact Array (ATCA) to search for emission from the $4_{-1} \rightarrow 3_{0}E$ transition of methanol (36.2 GHz) towards the center of the nearby starburst galaxy NGC253. Two regions of emission were…

Astrophysics of Galaxies · Physics 2015-06-22 Simon Ellingsen , Xi Chen , Hai-Hua Qiao , Willem Baan , Tao An , Juan Li , Shari Breen

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

A ring of dense molecular gas extending 2-7 pc orbits the supermassive black hole Sgr A* at the center of our Galaxy. Using the Green Bank Telescope, we detected water maser lines and both narrow (0.35 km/s) and broad (30 - 50 km/s)…

Astrophysics · Physics 2009-11-13 F. Yusef-Zadeh , J. Braatz , M. Wardle , D. Roberts

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…

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

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

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

OH(1720 MHz) and methanol masers are now recognized to be excellent probes of the interactions of supernova remnants with molecular clouds and tracers of massive star formation, respectively. To better understand the nature of star…

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

We report results of 6.7 GHz methanol maser monitoring of 139 star-forming sites with the Torun 32 m radio telescope from June 2009 to February 2013. The targets were observed at least once a month, with higher cadences of 2-4 measurements…

Astrophysics of Galaxies · Physics 2017-12-20 Marian Szymczak , Mateusz Olech , Rafał Sarniak , Paweł Wolak , Anna Bartkiewicz

Radio images of maser spots in the infrared source GL2789, connected with the young stellar object V645 Cyg, have been obtained as a result of the radio interferometric observations of H2O maser at 22 GHz and methanol maser at 6.7 GHz, with…

Astrophysics · Physics 2007-05-23 I. E. Val'tts , V. I. Slysh , M. A. Voronkov , V. Migenes

We present the first EVN maps of 6.7 GHz methanol masers of three high-mass protostar candidates selected from the Torun unbiased survey of the Galactic plane. A variety of linear and arc like structures was detected. A number of maser…

Astrophysics · Physics 2007-05-23 A. Bartkiewicz , M. Szymczak , H. J. van Langevelde

We report VLBI observations of methanol masers in the brightest 5(1)-6(0) A+ transition at 6.7 GHz in NGC 281W, 18151-1208 and 19388+2357. Using the fringe rate method absolute positions were obtained for all observed sources. A linear…

Astrophysics · Physics 2007-05-23 M. A. Voronkov , V. I. Slysh , F. Palagi , G. Tofani

Very luminous extragalactic water masers, the megamasers, are associated with active galactic nuclei (AGN) in galaxies characterized by accretion disks, radio jets, and nuclear outflows. Weaker masers, the kilomasers, seem to be mostly…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 A. Tarchi , P. Castangia , C. Henkel , G. Surcis , K. M. Menten

Four Class I maser sources were detected at 44, 84, and 95 GHz toward chemically rich outflows in the regions of low-mass star formation NGC 1333I4A, NGC 1333I2A, HH25, and L1157. One more maser was found at 36 GHz toward a similar outflow,…

Astrophysics of Galaxies · Physics 2015-06-04 S. V. Kalenskii , V. I. Slysh , L. E. B. Johansson , P. Bergman , S. Kurtz , P. Hofner , C. M. Walmsley

Water in outflows from protostars originates either as a result of gas-phase synthesis from atomic oxygen at T > 200 K, or from sputtered ice mantles containing water ice. We aim to quantify the contribution of the two mechanisms that lead…

Astrophysics of Galaxies · Physics 2015-06-18 Aleksi N. Suutarinen , Lars E. Kristensen , Joseph C. Mottram , Helen J. Fraser , Ewine F. van Dishoeck

We present the most complete to date interferometric study of the centimeter wavelength methanol masers detected in G358.93-0.03 at the burst and post-burst epochs. A unique, NIR/(sub)mm-dark and FIR-loud MYSO accretion burst was recently…

We present high angular resolution Submillimeter Array (SMA) and Karl G. Jansky Very Large Array (VLA) observations of the massive protocluster G18.67+0.03. Previously targeted in maser surveys of GLIMPSE Extended Green Objects (EGOs), this…

Astrophysics of Galaxies · Physics 2015-06-11 C. J. Cyganowski , C. L. Brogan , T. R. Hunter , Q. Zhang , R. K. Friesen , R. Indebetouw , C. J. Chandler