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The ATCA has been used to measure positions with arcsecond accuracy for 379 masers at the 22-GHz transition of water. The principal observation targets were 202 OH masers of the variety associated with star formation regions (SFR)s in the…

Astrophysics of Galaxies · Physics 2015-05-18 Shari Breen , James Caswell , Simon Ellingsen , Chris Phillips

A strong signature of a circumstellar disc around a high-mass protostar has been inferred from high resolution methanol maser observations in NGC7538-IRS1 N. This interpretation has however been challenged with a bipolar outflow proposed as…

Astrophysics of Galaxies · Physics 2015-05-13 M. Pestalozzi , M. Elitzur , J. Conway

We report a three year, 18 epoch, VLBI monitoring study of H2O masers in the sub-parsec, warped, accretion disk within the NGC4258 AGN. Our immediate goals are to trace the geometry of the underlying disk, track rotation via measurement of…

Astrophysics · Physics 2011-02-11 A. L. Argon , L. J. Greenhill , M. J. Reid , J. M. Moran , E. M. L. Humphreys

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

We report the results of a multi-epoch survey of water maser observations at 22.2 GHz with the Medicina radiotelescope from 44 bright rimmed clouds (BRCs) of the northern hemisphere identified by Sugitani et al. (1989) as potential sites of…

Astrophysics · Physics 2009-11-11 R. Valdettaro , F. Palla , J. Brand , R. Cesaroni

Following up on our discovery of terahertz water masers, reported in 2017, we report two further detections of water maser emission at frequencies above 1 THz. Using the GREAT instrument on SOFIA, we have detected emission in the 1.296411…

We have made multi-epoch VLBI observations of H2O maser emission in the massive star forming region IRAS 06061+2151 with the Japanese VLBI network (JVN) from 2005 May to 2007 October. The detected maser features are distributed within an…

We present VLBA observations of water maser emission associated with the star-forming region IRAS 21391+5802, which is embedded in a bright rimmed cometary globule in IC1396. The angular resolution of the maps is about 0.8 mas,…

Theoretical research on extragalactic masers (and hence this review) is almost entirely directed toward 22 GHz water masers in circumnuclear disks with the focus being the near ideal masing disk at the nucleus of the galaxy NGC4258. The…

Astrophysics · Physics 2007-05-23 William D. Watson

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

We have mapped 63 regions forming high-mass stars in CS J=5-4 using the CSO. The CS peak position was observed in C34S J=5-4 towards 57 cores and in 13CS J=5-4 towards the 9 brightest cores. The sample is a subset of a sample originally…

Astrophysics · Physics 2009-11-10 Yancy L. Shirley , Neal J Evans , Kaisa E. Young , Claudia Knez , Daniel T. Jaffe

We present the results of an ALMA survey to identify 183 GHz H$_2$O maser emission from AGN already known to host 22 GHz megamaser systems. Out of 20 sources observed, we detect significant 183 GHz maser emission from 13; this survey thus…

VLBA and EVN radio observations of H2O masers at 22 GHz and methanol masers at 6.7 GHz have been used to obtain images of the maser spots in the infrared object GL2789, which is associated with the young stellar object V645Cyg. The position…

Astrophysics · Physics 2009-11-07 V. I. Slysh , M. A. Voronkov , I. E. Val'tts , V. Migenes

We present an edge-on Keplerian disc model to explain the main component of the 12.2 and 6.7 GHz methanol maser emission detected toward NGC7538-IRS1 N. The brightness distribution and spectrum of the line of bright masers are successfully…

Astrophysics · Physics 2009-11-10 Michele R. Pestalozzi , Moshe Elitzur , John E. Conway , Roy S. Booth

We wish to perform a statistical study of the location and motion of individual 22 GHz water maser cloudlets, characterized by sizes that are within a few au, with respect to the radio thermal emission from young stellar objects (YSO). For…

Solar and Stellar Astrophysics · Physics 2020-03-25 Luca Moscadelli , Alberto Sanna , Ciriaco Goddi , Vasaant Krishnan , Fabrizio Massi , Francesca Bacciotti

AGB stars are the primary source of dust and complex molecules in the interstellar medium. The determination of outflow parameters is often hindered by the unknown geometry of the circumstellar environment, creating a demand for…

Solar and Stellar Astrophysics · Physics 2025-01-20 Boris S. Safonov , Sergey G. Zheltoukhov , Andrey M. Tatarnikov , Ivan A. Strakhov , Victor I. Shenavrin

We have observed the massive star forming region associated with the early B protostar G192.16-3.84 in NH3(1,1), 22.2 GHz water masers, 1.3 cm continuum emission, and at 850 microns. The dense gas associated with G192.16 is clumpy,…

Astrophysics · Physics 2009-11-10 D. S. Shepherd , T. Borders , M. Claussen , Y. Shirley , S. E. Kurtz

Using the Very Large Array (VLA) of the National Radio Astronomy Observatory in the A and B configurations, we have obtained simultaneous high resolution observations of both the 22 GHz water maser lines as well as the 22 GHz continuum for…

Astrophysics · Physics 2008-11-26 E. J. McGrath , W. M. Goss , C. G. De Pree

We report the discovery of H2O maser emission at 1.35 cm wavelength in seven active galactic nuclei (at distances up to <80 Mpc) during a survey conducted at the 70-m diameter antenna of the NASA Deep Space Network near Canberra, Australia.…

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
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