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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 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 report accurate laboratory measurements of selected methanol transition frequencies between 0.834 and 230 GHz in order to facilitate astronomical velocity analyses. New data have been obtained between 10 and 27 GHz and between 60 and 119…

Astrophysics · Physics 2011-03-02 H. S. P. Mueller , K. M. Menten , H. Maeder

We present a comprehensive analysis of the periodic flares observed in the 6.7 GHz methanol transition in G22.356+0.066, utilizing the Maxwell-Bloch equations (MBEs) as a framework to model these phenomena. By solving the one-dimensional…

High Energy Astrophysical Phenomena · Physics 2024-09-17 T. Rashidi , V. Anari , A. Bartkiewicz , P. Wolak , M. Szymczak , F. Rajabi

Star formation is underway in the W49N molecular cloud (MC) at a high level of efficiency, with almost twenty ultra-compact (UC) HII regions observed thus far, indicating a recent formation of massive stars. Previous works have suggested…

Astrophysics of Galaxies · Physics 2023-09-19 Mendoza-Torres , J. E. , Juárez-Gama , M. , Rodríguez-Esnard , I. T

Faraday tomography, the study of the distribution of extended polarized emission by strength of Faraday rotation, is a powerful tool for studying magnetic fields in the interstellar medium of our Galaxy and nearby galaxies. The strong…

Astrophysics of Galaxies · Physics 2018-10-24 Cameron L. Van Eck

We report the results of the first complete survey of an area of the Galactic Plane for maser emission from the 6.7-GHz transition of methanol. The survey covers a 10.6-square-degree region of the Galactic Plane in the longitude range…

We present molecular-line observations at millimetre, centimetre and infrared wavelengths of the region containing OH(1720 MHz) masers in the supernova remnant (SNR) G349.7+0.2, using the Australia Telescope (AT) Mopra antenna, the…

Astrophysics · Physics 2011-04-20 J. S. Lazendic , M. Wardle , J. B. Whiteoak , M. G. Burton , A. J. Green

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

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

The hydroxyl radical (OH) is found in various environments within the interstellar medium (ISM) of the Milky Way and external galaxies, mostly either in diffuse interstellar clouds or in the warm, dense environments of newly formed low-mass…

Recently, a comparison between the locations of 6.7-GHz methanol masers and dust continuum emission has renewed speculation that these masers can be associated with evolved stars. The implication of such a scenario would be profound,…

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

Strong singly-ionized magnesium (MgII) absorption lines in quasar spectra typically serve as a proxy for intervening galaxies along the line of sight. Previous studies have found a correlation between the number of these MgII absorbers and…

Astrophysics of Galaxies · Physics 2014-10-16 J. S. Farnes , S. P. O'Sullivan , M. E. Corrigan , B. M. Gaensler

Results of the long-term monitoring observations of the 6.7 GHz Class II methanol masers associated with the four high-mass star-forming regions by Hitachi 32-m radio telescope are presented. We detected periodic flux variability in…

Astrophysics of Galaxies · Physics 2024-02-28 Yoshihiro Tanabe , Yoshinori Yonekura

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

The first images of 6.7-GHz methanol masers in the massive star-forming regions DR21(OH) and DR21(OH)N are presented. By measuring the shapes, radial velocities and polarization properties of these masers it is possible to map out the…

Astrophysics · Physics 2009-11-13 L. Harvey-Smith , R. Soria-Ruiz , A. Duarte-Cabral , R. J. Cohen

The present paper focuses on the high-mass star-forming region G16.59-0.05. Methods: Using the VLBA and the EVN arrays, we conducted phase-referenced observations of the three most powerful maser species in G16.59-0.05: 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

To investigate whether distinctions exist between low and high-luminosity Class II 6.7-GHz methanol masers, we have undertaken multi-line mapping observations of various molecular lines, including the NH3(1,1), (2,2), (3,3), (4,4) and…

Astrophysics of Galaxies · Physics 2010-07-13 Y. W. Wu , Y. Xu , J. D. Pandian , J. Yang , C. Henkel , K. M. Menten , S. B. Zhang

We demonstrate absorber-free passive and hybrid mode-locking at sub-GHz repetition rates using a hybrid integrated extended cavity diode laser around 1550 nm. The laser is based on InP as gain medium and a long Si$_3$N$_4$ feedback circuit,…