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High-resolution VLA observations of 1720 MHz OH maser emission from Sgr A East and the circumnuclear disk with spatial and spectral resolutions of $\approx$ 2\dasec5 $\times$ 1\dasec3 and 0.27 \kms are reported. This follow-up observational…

Astrophysics · Physics 2009-10-30 F. Yusef-Zadeh , D. A. Roberts , W. M. Goss , D. A. Frail , A. J. Green

We have searched for massive molecular outflows in a sample of high-mass star forming regions, and we have characterised both the outflow properties and those of their associated molecular clumps. With a sample composed largely of more…

Astrophysics of Galaxies · Physics 2015-05-13 A. Lopez-Sepulcre , C. Codella , R. Cesaroni , N. Marcelino , C. M. Walmsley

We present a (sub)millimeter line survey of the methanol maser outflow located in the massive star-forming region DR21(OH) carried out with the Submillimeter Array (SMA) at 217/227 GHz and 337/347 GHz. We find transitions from several…

Solar and Stellar Astrophysics · Physics 2018-12-26 Ma. T. Orozco-Aguilera , Antonio Hernández-Gómez , Luis A. Zapata

Four Class I maser sources were detected at 44, 84, and 95 GHz toward chemically rich outflows in the regions of low-mass star formation NGC 1333I4A, NGC 1333I2A, HH25, and L1157. One more maser was found at 36 GHz toward a similar outflow,…

Astrophysics of Galaxies · Physics 2015-06-04 S. V. Kalenskii , V. I. Slysh , L. E. B. Johansson , P. Bergman , S. Kurtz , P. Hofner , C. M. Walmsley

We present linear and circular polarization observations of the water masers in 4 distinct regions spread over 1x2 arcseconds around the HW2 high-mass young stellar object in the Cepheus A star-forming region. We find magnetic fields…

Astrophysics · Physics 2009-11-11 W. H. T. Vlemmings , P. J. Diamond , H. J. van Langevelde , J. M Torrelles

A comparison between the observed light curves of periodic masers in G9.62+0.20E and G188.95+0.89 and the results of a simple colliding-wind binary model is made to establish whether the flaring and other time-dependent behaviour of the…

Astrophysics of Galaxies · Physics 2015-05-27 DJ van der Walt

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

Using the Submillimeter Array (SMA) we have imaged for the first time the 321.226 GHz, 10_{29}-9_{36} ortho-H2O maser emission. This is also the first detection of this line in the Cepheus A high-mass star-forming region. The 22.235 GHz,…

Astrophysics · Physics 2009-11-13 N. A. Patel , S. Curil , Q. Zhang , T. K. Sridharan , P. T. P. Ho , J. M. Torrelles

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 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 discovery of the first 14NH3 (2,2) maser, seen in the Sgr B2 Main star forming region near the center of the Milky Way, using data from the Very Large Array radio telescope. The maser is seen in both lower resolution (3" or…

Water megamasers at 22 GHz with a gas disk configuration in galaxies provide the most precise measurements of supermassive black hole masses, as well as independent constraints on the Hubble constant in the nearby universe. The existence of…

Astrophysics of Galaxies · Physics 2021-08-18 Man I Lam , C. Jakob Walcher , Feng Gao , Ming Yang , Huan Li , Lei Hao

Using the Green Bank Telescope, we conducted a ``snapshot'' survey for water maser emission toward the nuclei of 611 galaxies and detected eight new sources. The sample consisted of nearby (v < 5000 km/s) and luminous (M_B < -19.5)…

Astrophysics · Physics 2010-11-11 J. A. Braatz , N. E. Gugliucci

High resolution maps of maser emission provide very detailed information on processes occurring in circumstellar envelopes of late-type stars. A particularly detailed picture of the innermost shells around AGB stars is provided by SiO…

Solar and Stellar Astrophysics · Physics 2009-06-02 Francisco Colomer

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

Recent observations have revealed that starburst galaxies can drive molecular gas outflows through stellar radiation pressure. Molecular gas is the phase of the interstellar medium from which stars form, so these outflows curtail stellar…

After the discovery of space masers based on OH radicals (Weaver et al, 1965) and H2O (Cheung et al, 1969) such microwave lasers have been found to work in more than 100 molecular species (Elitzur, 1992; Townes, 1997), as well as in highly…

Astrophysics · Physics 2009-11-10 S. Johansson , V. S. Letokhov

The optical filaments found in many cooling flows in galaxy clusters consist of low density ($\sim 10^3 \pcc$) cool ($\sim 10^3$ K) gas surrounded by significant amounts of cosmic-ray and magnetic-field energy. Their spectra show…

A short Chandra ACIS-S observation of the Seyfert 2 galaxy IC 2560, which hosts a luminous nuclear water megamaser, shows: 1) the X-ray emission is extended; 2) the X-ray spectrum shows emission features in the soft (E<2 keV) X-ray band;…

Astrophysics · Physics 2009-11-07 K. Iwasawa , P. R. Maloney , A. C. Fabian

Water masers are common in star-forming regions (SFRs), with the 22.235 GHz transition widely detected in both high- and low-mass protostars. In contrast, (sub)millimeter water maser transitions remain poorly studied, especially in low-mass…

Astrophysics of Galaxies · Physics 2025-09-17 P. K. Humire , C. Goddi , G. N. Ortiz-León , A. Hernández-Gómez , J-C Loison
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