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The University of Tasmania Mt Pleasant 26-m and Ceduna 30-m radio telescopes have been used to search for 6.7-GHz class II methanol masers towards two hundred GLIMPSE sources. The target regions were selected on the basis of their…

Astrophysics · Physics 2008-11-26 S. P. Ellingsen

The NGC 1333 IRAS 4 region was observed in the 22 GHz H2O maser line with an angular resolution of about 0.08 arcseconds. Two groups of masers were detected, one near IRAS 4A and the other near BI. Among the eight maser spots detected near…

Astrophysics · Physics 2009-11-13 Geumsook Park , Minho Choi

The Australia Telescope Compact Array (ATCA) has been used to make the first extensive search for the class I methanol masers at 9.9 GHz. In total, 48 regions of high-mass star formation were observed. In addition to masers in W33-Met…

Astrophysics of Galaxies · Physics 2015-05-18 M. A. Voronkov , J. L. Caswell , S. P. Ellingsen , A. M. Sobolev

We present 247-GHz molecular line observations of methanol (CH$_3$OH) toward sixteen massive star-forming regions, using the APEX telescope with an angular resolution of $25''$. The sample covers a range of evolutionary states, including…

We report the first multi-epoch milliarcsecond resolution imaging of the 6.7-GHz class II methanol maser emission associated with the high-mass protocluster system NGC6334I. The observations covered a period of over 10 years in four epochs…

We have investigated the central region of NGC 253 for the presence of 84.5-GHz ($5_{-1}\rightarrow4_0$E) methanol emission using the Australia Telescope Compact Array. We present the second detection of 84.5-GHz class~I methanol maser…

Astrophysics of Galaxies · Physics 2018-11-21 Tiege P. McCarthy , Simon P. Ellingsen , Shari L. Breen , Maxim A. Voronkov , Xi Chen

We report on the first multi-epoch, phase referenced VLBI observations of the water maser emission in a high-mass protostar associated with a disk-jet system. The source under study, IRAS 20126+4104, has been extensively investigated in a…

Astrophysics · Physics 2009-11-11 L. Moscadelli , R. Cesaroni , M. J. Rioja

High mass stars play an important role in the Interstellar Medium, but much remains to be known about their formation. Class I methanol masers may be unique tracers of an early stage of high mass star formation, and a better understanding…

Astrophysics of Galaxies · Physics 2022-05-18 Nycole Wenner , A. P. Sarma , E. Momjian

We present a search for water maser emission at 22 GHz associated with young low-mass protostars in six HII regions -- M16, M20, NGC 2264, NGC 6357, S125, and S140. The survey was conducted with the NRAO Very Large Array from 2000 to 2002.…

Astrophysics · Physics 2009-11-10 Kevin R. Healy , J. Jeff Hester , Mark J. Claussen

In this contribution I will attempt to show that the study of galactic 6.7 and 12.2GHz methanol masers themselves, as opposed to the use of methanol masers as signposts, can yield important conclusions contributing to the understanding of…

Astrophysics · Physics 2009-11-13 Michele Pestalozzi

Methanol masers and molecular shock tracers were observed in the W3(OH)/W3(H$_2$O) region with the BIMA array and the Onsala 20m radiotelescope. Characteristics of the outflows in the region are discussed. A model of the W3(OH) methanol…

The goal of the Protostellar Outflows at the EarliesT Stages (POETS) survey is to image the disk-outflow interface on scales of 10-100 au in a statistically significant sample (36) of luminous young stellar objects (YSO), targeting both the…

Solar and Stellar Astrophysics · Physics 2019-10-23 Luca Moscadelli , Alberto Sanna , Ciriaco Goddi , Vasaant Krishnan , Fabrizio Massi , Francesca Bacciotti

We report the discovery of water maser emission in five active galactic nuclei (AGN) with the 100-m Green Bank Telescope (GBT). The positions of the newly discovered masers, measured with the VLA, are consistent with the optical positions…

Astrophysics · Physics 2008-11-26 Paul T. Kondratko , Lincoln J. Greenhill , James M. Moran

Class II methanol (CH$_{3}$OH) masers are amongst the clearest signposts of recent high-mass star formation (HMSF). A complete catalogue outlines the distribution of star formation in the Galaxy, the number of young star-forming cores, and…

The present paper focuses on the high-mass star-forming region G23.01-0.41. Methods: Using the VLBA and the EVN arrays, we conducted phase-referenced observations of the three most powerful maser species in G23.01-0.41: H2O at 22.2 GHz (4…

Astrophysics of Galaxies · Physics 2015-05-18 A. Sanna , L. Moscadelli , R. Cesaroni , A. Tarchi , R. S. Furuya , C. Goddi

Water megamaser emission at 22 GHz has proven to be a powerful tool for astrophysical studies of AGN allowing an accurate determination of the central black hole mass and of the accretion disc geometry and dynamics. However, after searches…

We present high angular resolution (FWHM_beam < 0.2") observations of the 23.1-GHz methanol (CH_3OH) transition toward the massive-star forming region NGC 7538 IRS 1. The two velocity components previously reported by Wilson et al. are…

Astrophysics of Galaxies · Physics 2015-05-18 Roberto Galván-Madrid , Gabriela Montes , Edgar A. Ramírez , Stan Kurtz , Esteban Araya , Peter Hofner

We report the result of a systematic methanol observation toward IRAS 19312+1950. The properties of the SiO, H2O and OH masers of this object are consistent with those of mass-losing evolved stars, but some other properties are difficult to…

Solar and Stellar Astrophysics · Physics 2015-08-06 Jun-ichi Nakashima , Andrej M. Sobolev , Svetlana V. Salii , Yong Zhang , Bosco H. K. Yung , Shuji Deguchi

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

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
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