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Methanol is a key species in astrochemistry since it is the most abundant organic molecule in the ISM and is thought to be the mother molecule of many complex organic species. Estimating the deuteration of methanol around young protostars…

The 6.7 GHz methanol maser is exclusively associated with high-mass star formation. However, it remains unclear what structures harbour the methanol masers. Cepheus A is one of the closest regions of massive star formation, making it an…

太阳与恒星天体物理 · 物理学 2015-05-20 K. J. E. Torstensson , H. J. van Langevelde , W. H. T. Vlemmings , S. Bourke

We present (sub)millimeter imaging at 0.5'' resolution of the massive star-forming region G358.93-0.03 acquired in multiple epochs at 2 and 3 months following the recent flaring of its 6.7 GHz methanol maser emission. Using SMA and ALMA, we…

Class I methanol masers are believed to be produced in the shock-excited environment around star-forming regions. Many authors have argued that the appearance of various subsets of class I masers may be indicative of specific evolutionary…

We report on the interferometric detection of 36.2 GHz Class I methanol emission with the new 27-40 GHz Ka band receivers available on the Expanded Very Large Array (EVLA). The brightness temperatures of the interferometric 36 GHz…

星系天体物理 · 物理学 2015-05-18 Lorant O. Sjouwerman , Ylva M. Pihlstrom , Vincent L. Fish

Methanol, one of the simplest complex organic molecules in the Interstellar Medium (ISM), has been shown to be present and extended in cold environments such as starless cores. We aim at studying methanol emission across several starless…

High-mass stars are thought to accumulate much of their mass via short, infrequent bursts of disk-aided accretion. Such accretion events are rare and difficult to observe directly but are known to drive enhanced maser emission. In this…

Methanol is formed via surface reactions on icy dust grains. Methanol is also detected in the gas-phase at temperatures below its thermal desorption temperature and at levels higher than can be explained by pure gas-phase chemistry. The…

太阳与恒星天体物理 · 物理学 2018-05-02 N. F. W. Ligterink , C. Walsh , R. G. Bhuin , S. Vissapragada , J. Terwisscha van Scheltinga , H. Linnartz

Context: Methanol masers at 6.7GHz are recognised markers of high-mass star formation regions. The study of their distribution in the Galaxy gives important insights into the star formation activity of the Milky Way. We present a…

天体物理学 · 物理学 2009-11-11 Michele R. Pestalozzi , A. Chrysostomou , J. Collett , V. Minier , J. Conway , R. Booth

Context: High-mass young stellar objects (HMYSOs) can undergo accretion episodes that strongly affect the star evolution, the dynamics of the disk, and its chemical evolution. Recently reported extraordinary bursts in the methanol maser…

星系天体物理 · 物理学 2018-09-19 Marian Szymczak , Mateusz Olech , Paweł Wolak , Eric Gérard , Anna Bartkiewicz

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…

星系天体物理 · 物理学 2015-06-11 S. P. Ellingsen , A. M. Sobolev , D. M. Cragg , P. D. Godfrey

We present a second epoch of observations of the 44 GHz Class I methanol maser line toward the star forming region OMC-2. The observations were carried out with the Very Large Array, and constitute one of the first successful Zeeman effect…

星系天体物理 · 物理学 2015-06-11 E. Momjian , A. P. Sarma

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…

星系天体物理 · 物理学 2015-05-13 A. Bartkiewicz , M. Szymczak , H. J. van Langevelde , A. M. S. Richards , Y. M. Pihlstrom

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…

太阳与恒星天体物理 · 物理学 2015-11-18 Hyunwoo Kang , Kee-Tae Kim , Do-Young Byun , Seokho Lee , Yong-Sun Park

We present the results of the further investigation of the Class II methanol maser emission in the $14_1 - 14_0$ A$^{-+}$ transition at 349.1 GHz discovered in 2016 in the remarkable core S255IR-SMA1, harboring a $\sim$20 M$_\odot$…

星系天体物理 · 物理学 2025-08-01 I. I. Zinchenko , S. V. Salii , A. M. Sobolev , I. A. Zaichikova , S. -Y. Liu , Y. -N. Su

We present a survey of the polarization properties of mm-wavelength methanol masers, comprising both classes, and transitions from 84.5 to 157.0 GHz. Linear polarization is found in more than half of the observed objects, and circular…

天体物理学 · 物理学 2009-11-10 Helmut Wiesemeyer , Clemens Thum , Malcolm Walmsley

A number of mechanisms to understand the periodic class II methanol masers associated with some high-mass star forming regions have been proposed in the past. Two recent proposals, ie. by Parfenov &Sobolev (2014) and Sanna et al. (2015)…

星系天体物理 · 物理学 2016-03-16 DJ van der Walt , JM Maswanganye , S Etoka , S Goedhart , SP van den Heever

Methanol (CH$_{3}$OH) is a key complex organic molecule (COM) in the interstellar medium, widely used as a tracer of dense gas and hot molecular cores (HMCs). Using high-resolution ALMA observations from the ATOMS survey, we investigate the…

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…

星系天体物理 · 物理学 2015-05-18 Roberto Galván-Madrid , Gabriela Montes , Edgar A. Ramírez , Stan Kurtz , Esteban Araya , Peter Hofner

A 3D maser model has been used to perform an inverse problem on the light curves from three high-amplitude maser flares, selected on the basis of contemporaneous infra-red observations. Plots derived from the model recover the size of the…

太阳与恒星天体物理 · 物理学 2020-07-08 M. D. Gray , S. Etoka , B. Pimpanuwat