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Related papers: VLBI multi-epoch water maser observations toward m…

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This is a report on detailed modeling of young high-mass protostellar candidates during their most embedded and obscured phases. We performed narrowband mid-infrared imaging of three candidate high-mass protostellar objects in G11.94-0.62,…

Astrophysics · Physics 2009-11-13 James M. De Buizer , Mayra Osorio , Nuria Calvet

Very Long Baseline Interferometry (VLBI) provides high angular resolution images and has been used for stellar astrometry for decades. The DYNAMO-VLBA project utilizes the Very Long Baseline Array (VLBA) to study tight binary and multiple…

Solar and Stellar Astrophysics · Physics 2025-11-07 Jazmin Ordonez-Toro , Sergio A. Dzib , Laurent Loinard

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…

Solar and Stellar Astrophysics · Physics 2015-05-20 K. J. E. Torstensson , H. J. van Langevelde , W. H. T. Vlemmings , S. Bourke

Observations of the masers in the course of RadioAstron mission yielded detections of fringes for a number of sources in both water and hydroxyl maser transitions. Several sources display numerous ultra-compact details. This proves that…

Astrophysics of Galaxies · Physics 2018-08-22 A. M. Sobolev , N. N. Shakhvorostova , A. V. Alakoz , W. A. Baan

Several radio sources have been detected in the HMSFR W75N(B), among them the massive YSOs VLA1 and VLA2 are of great interest. These are thought to be in different evolutionary stages. In particular, VLA1 is at the early stage of the…

Interstellar masers are unique probes of the environments in which they arise. In studies of high-mass star formation their primary function has been as signposts of these regions and they have been used as probes of the kinematics and…

Astrophysics · Physics 2009-11-13 S. P. Ellingsen , M. A. Voronkov , D. M. Cragg , A. M. Sobolev , S. L. Breen , P. D. Godfrey

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 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 used the Very Long Baseline Array (VLBA) and the European VLBI Network (EVN) to perform phase-referenced VLBI observations of the three most powerful maser transitions associated with the high-mass star-forming region G28.87+0.07: the…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. J. Li , L. Moscadelli , R. Cesaroni , R. S. Furuya , Y. Xu , T. Usuda , K. M. Menten , M. Pestalozzi , D. Elia , E. Schisano

The current paradigm of star formation through accretion disks, and magnetohydrodynamically driven gas ejections, predicts the development of collimated outflows, rather than expansion without any preferential direction. We present radio…

We present a study of molecular outflows using high-resolution mapping of the CO (1-0) line emission toward eight relatively nearby 6.7 GHz methanol masers, which are associated with massive star forming regions. Outflows were detected in…

Astrophysics · Physics 2008-11-26 Y. Xu , Z. -Q. Shen , J. Yang , X. W. Zheng , A. Miyazaki , K. Sunada , H. J. Ma , J. J. Li , J. X. Sun , C. C. Pei

Class II CH3OH masers are used as a convenient tracer of disc-like structures in high-mass star formation. However, more than half of them show a complex distribution in Very Long Baseline Interferometry (VLBI) maps. The origin of such a…

Solar and Stellar Astrophysics · Physics 2023-10-05 M. Nakamura , K. Motogi , H. Nakamura , Y. Yonekura , K. Fujisawa

We have performed observations of water maser emission towards a sample of low-mass protostars, in order to investigate the properties of jets associated with the earliest stages of star formation and their interaction with the surrounding…

Astrophysics of Galaxies · Physics 2015-05-13 J. -F. Desmurs , C. Codella , J. Santiago-Garcia , M. Tafalla , R. Bachiller

We present Very Long Baseline Interferometry (VLBI) observations of 22 GHz H$_2$O masers in the high-mass star-forming region of \objectname{W75N}, carried out with VLBI Exploration of Radio Astrometry (VERA) for three-epochs in 2007 with…

We imaged the protostars of the nearby region NGC1333 IRAS 4 in the water maser line at 22.2 GHz by using the VLBA in phase referencing at milliarcsecond scale over four epochs spaced by one month to measure proper motions. We measure the…

Astrophysics · Physics 2008-11-12 J. -F. Desmurs , C. Codella , J. Santiago-Garcia , M. Tafalla , R. Bachiller

Highly collimated jets found in AGB and post-AGB stars are expected to play an important role for shaping planetary nebulae. Recent VLBI observations of H2O maser sources have revealed that some of the spatio-kinematical structures of H2O…

Astrophysics · Physics 2009-11-13 Hiroshi Imai

The 22.2 GHz water masers are often associated with the 6.7 GHz methanol masers but owing to the different excitation conditions they likely probe independent spatial and kinematic regions around the powering young massive star. We compared…

Astrophysics of Galaxies · Physics 2015-06-04 Anna Bartkiewicz , Marian Szymczak , Huib Jan van Langevelde

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

Theoretical simulations and observations at different angular resolutions have shown that magnetic fields have a central role in massive star formation. Like in low-mass star formation, the magnetic field in massive young stellar objects…

Solar and Stellar Astrophysics · Physics 2015-06-17 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , B. Hutawarakorn Kramer , A. Bartkiewicz , M. G. Blasi

We present a survey in the 6_{16}-5_{23} rotational water transition toward 33 galactic ultracompact HII regions. Maser emission is detected toward 18 of these sources; two are new detections. High quality spectra are provided for all 18…

Astrophysics · Physics 2008-11-26 S. Kurtz , P. Hofner