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We characterize the molecular environment of candidate massive young stellar objects (MYSOs) signposted by methanol masers. Single pixel observations of 10 transitions of HCO^+, CO and CS isotopomers were carried out, using the IRAM 30m…

Astrophysics · Physics 2009-11-13 M. Szymczak , A. Bartkiewicz , A. M. S. Richards

We have used the ATNF Mopra antenna and the SEST antenna to search in the directions of several class II methanol maser sources for emission from six methanol transitions in the frequency range 85-115 GHz. The transitions were selected from…

We report the first detection of a methanol maser in the 10(1)-9(2)A- transition at 23.4 GHz, discovered during the H2O southern Galactic Plane Survey (HOPS) with the 22-m Mopra radio telescope. In the region covered by HOPS, the 23.4 GHz…

Astrophysics of Galaxies · Physics 2015-05-20 M. A. Voronkov , A. J. Walsh , J. L. Caswell , S. P. Ellingsen , S. L. Breen , S. N. Longmore , C. R. Purcell , J. S. Urquhart

In the early days of methanol maser discoveries the 9(2)-10(1) A+ transition at 23.1 GHz was found to exhibit maser characteristics in the northern star-forming region W3(OH), and probable maser emission in two other sources. Attention…

Astrophysics · Physics 2009-11-10 D. M. Cragg , A. M. Sobolev , J. L. Caswell , S. P. Ellingsen , P. D. Godfrey

Time series are presented for the class II methanol maser source G12.89+0.49, which has been monitored for nine years at the Hartebeesthoek Radio Astronomy Observatory. The 12.2 and 6.7 GHz methanol masers were seen to exhibit rapid,…

Astrophysics of Galaxies · Physics 2015-05-13 S. Goedhart , M. C. Langa , M. J. Gaylard , D. J. van der Walt

Methanol masers at 6.7 GHz are associated with high-mass star-forming regions (HMSFRs) and often have mid-infrared (MIR) counterparts characterized by extended emission at 4.5 $\mu$m, which likely traces outflows from massive young stellar…

Astrophysics of Galaxies · Physics 2014-05-08 Anna Bartkiewicz , Marian Szymczak , Huib van Langevelde

We apply Dicke's theory of superradiance introduced in 1954 to the methanol 6.7 GHz and water 22 GHz spectral lines, often detected in molecular clouds as signposts for the early stages of the star formation process. We suggest that…

Astrophysics of Galaxies · Physics 2017-04-06 Fereshteh Rajabi , Martin Houde

We report a multi-epoch, simultaneous 22 GHz H2O and 44 GHz class I CH3OH maser line survey towards 180 intermediate-mass young stellar objects, including 14 Class 0, 19 Class I objects, and 147 Herbig Ae/Be stars. We detected H2O and CH3OH…

Astrophysics of Galaxies · Physics 2015-05-30 Jae-Han Bae , Kee-Tae Kim , So-Young Youn , Won-Ju Kim , Do-Young Byun , Hyunwoo Kang , Chung Sik Oh

We have used the Australia Telescope National Facility Mopra 22m millimetre telescope to search for emission from the 85.5-GHz and 86.6-GHz transitions of methanol. The search was targeted towards 22 star formation regions which exhibit…

Astrophysics · Physics 2009-11-07 S. P. Ellingsen , D. M. Cragg , V. Minier , E. Muller , P. D. Godfrey

We investigate which structures the 6.7 GHz methanol masers trace in the environment of high-mass protostar candidates by observing a homogenous sample of methanol masers selected from Torun surveys. We also probed their origins by looking…

Astrophysics of Galaxies · Physics 2015-05-13 A. Bartkiewicz , M. Szymczak , H. J. van Langevelde , A. M. S. Richards , Y. M. Pihlstrom

We report the results of a sensitive search for 12.2 GHz methanol maser emission towards a sample of eight high-mass star formation regions in the Large Magellanic Clouds which have been detected in other maser transitions. We detected one…

Astrophysics of Galaxies · Physics 2015-05-14 S. P. Ellingsen , S. L. Breen , J. L. Caswell , L. J. Quinn , G. A. Fuller

Very long baseline interferometry (VLBI) monitoring of the 6.7 GHz methanol maser allows us to measure the internal proper motions of the maser spots and therefore study the gas motion around high-mass young stellar objects. To this end, we…

Methanol masers are associated with young high-mass stars and are an important tool for investigating the process of massive star formation. The recently discovered methanol maser ring in G23.657-00.127 provides an excellent ``laboratory''…

Astrophysics · Physics 2008-12-18 A. Bartkiewicz , A. Brunthaler , M. Szymczak , H. J. van Langevelde , M. J. Reid

The results of a maser survey toward ninety-nine protostars in the Orion molecular cloud complex are presented. The target sources are low-mass protostars identified from infrared observations. Single-dish observations were carried out in…

Astrophysics of Galaxies · Physics 2015-06-17 Miju Kang , Jeong-Eun Lee , Minho Choi , Yunhee Choi , Kee-Tae Kim , James Di Francesco , Yong-Sun Park

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…

We report on the periodic flux variations in the 6.7 GHz $\mathrm{CH_3OH}$ maser associated with the high-mass protostar G353.273+0.641, based on 13 yr of monitoring mainly by the Hitachi 32 m telescope. We identified a periodicity of 309…

Solar and Stellar Astrophysics · Physics 2026-02-04 Sohta Harajiri , Kazuhito Motogi , Ryota Nakamura , Yoshinori Yonekura , Yoshihiro Tanabe , Kenta Fujisawa

The Australia Telescope Compact Array (ATCA) has been used to map class I methanol masers at 36 and 44 GHz in G309.38-0.13. Maser spots are found at nine locations in an area of 50''x30'', with both transitions reliably detected at only two…

Astrophysics of Galaxies · Physics 2015-05-19 M. A. Voronkov , J. L. Caswell , T. R. Britton , J. A. Green , A. M. Sobolev , S. P. Ellingsen

Periodic or regular flaring of class II methanol masers in nine high mass star forming regions is now a well established phenomenon. Amongst the nine star forming regions, G37.55+0.20 is the only case at present where apart from the…

Astrophysics of Galaxies · Physics 2015-06-18 D. J. van der Walt

An Australia Telescope Compact Array search for 22 GHz water masers towards 6.7 GHz class II methanol masers detected in the Methanol Multibeam (MMB) survey has resulted in the detection of extremely high velocity emission from one of the…

Astrophysics of Galaxies · Physics 2015-06-16 A. M. Titmarsh , S. P. Ellingsen , S. L. Breen , J. L. Caswell , M. A. Voronkov

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