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Related papers: OH(1720 MHz) Masers at the Galactic Centre

200 papers

We present a survey of OH maser emission towards a sample of high mass protostellar objects made using the Nancay and GBT telescopes.OH maser emission was detected towards 63 objects with 36 new detections. There are 56 star-forming regions…

Astrophysics · Physics 2009-11-13 K. A. Edris , G. A. Fuller , R. J . Cohen

We present global VLBI observations of the first-excited state OH masers in the massive star-forming region Onsala 1 (ON 1). The 29 masers detected are nearly all from the 6035 MHz transition, and nearly all are identifiable as Zeeman pair…

Astrophysics of Galaxies · Physics 2010-04-23 Vincent L. Fish , Loránt O. Sjouwerman

The aim of this study is to investigate the physical properties of molecular envelopes of planetary nebulae in their earliest stages of evolution. Using the 100m telescope at Effelsberg, we have undertaken a high sensitivity discrete source…

Solar and Stellar Astrophysics · Physics 2015-05-20 J. -F. Desmurs , A. Baudry , P. Sivagnanam , C. Henkel , A. M. S. Richards , I. Bains

We present MERLIN observations of the continuum (both 1.6 and 5 GHz) and OH maser emission towards Arp220. the correct spatial configuration of the various componnents of the galaxy is revealed. In the eastern component the masers are shown…

We have used the Australia Telescope Compact Array (ATCA) to make a sensitive search for maser emission from the 4765-MHz transition of OH towards a sample of 55 star formation regions. Maser emission with peak flux densities in excess of…

Astrophysics · Physics 2007-05-23 R. Dodson , S. Ellingsen

We present results of a high resolution survey of OH masers in Galactic Star Forming Regions in order to study the maser emission and establish a list of suitable candidates for higher resolution instruments follow up. We used the Very Long…

Astrophysics · Physics 2007-05-23 A. E. Ruiz-Velasco , V. Migenes , V. Slysh , I. E. Val'tts

The 6 cm and 20 cm radio continuum properties of all 85 galaxies with reported 22 GHz H2O maser emission and luminosity distance D > 0.5 Mpc are studied. For the total of 55 targets for which both 6 cm and 20 cm measurements exist and for…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 J. S. Zhang , C. Henkel , Q. Guo , J. Wang

High signal-to-noise spectra toward background quasars are crucial for uncovering weak absorption in the circumgalactic medium (CGM) of intervening galaxies, such as the diagnostic lines of N V that provide insight to the ionization process…

MHD simulations show that the magnetic field can drive molecular outflows during the formation of massive protostars. The best probe to observationally measure both the morphology and the strength of this magnetic field at scales of 10-100…

Solar and Stellar Astrophysics · Physics 2019-03-20 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , B. Hutawarakorn Kramer , A. Bartkiewicz

We present VLBA observations of the ground-state hydroxyl masers in W3(OH) at 0.02 km s-1 spectral resolution. Over 250 masers are detected, including 56 Zeeman pairs. Lineshapes are predominantly Gaussian or combinations of several…

Astrophysics · Physics 2008-11-26 Vincent L. Fish , Walter F. Brisken , Loránt O. Sjouwerman

We present the results of a survey, the deepest to date, for HI emission at 21 cm and OH emission at 18 cm (lines at 1612, 1665, 1667 and 1720 MHz) in the direction towards the Galactic globular clusters M 15, M 2, NGC 6934, NGC 7006 and…

Astrophysics · Physics 2009-11-13 Jacco Th. van Loon , Snezana Stanimirovic , A. Evans , Erik Muller

We present a parsec-scale image of the OH maser in the nucleus of the active galaxy IIIZw35, made using the Very Long Baseline Array at a wavelength of 18 cm. We detected two distinct components, with a projected separation of 50 pc (for…

Astrophysics · Physics 2016-08-30 A. S. Trotter , J. M. Moran , L. J. Greenhill , X. -W. Zheng , C. R. Gwinn

We aim to detect the magnetic field and infer its properties around four AGB stars using H$_2$O maser observations. The sample we observed consists of the following sources: the semi-regular variable RT Vir and the Mira variables AP Lyn, IK…

Solar and Stellar Astrophysics · Physics 2015-06-15 M. L. Leal-Ferreira , W. H. T. Vlemmings , A. Kemball , N. Amiri

OH(1720 MHz) and methanol masers are now recognized to be excellent probes of the interactions of supernova remnants with molecular clouds and tracers of massive star formation, respectively. To better understand the nature of star…

Cosmic-ray and X-ray ionisations in molecular gas produce a weak far-ultraviolet flux through the radiative decay of H2 molecules that have been excited by collisions with energetic electrons (the Prasad-Tarafdar mechanism). I consider the…

Astrophysics · Physics 2009-10-31 Mark Wardle

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

The collisional pumping of CH3OH and OH masers in non-dissociative C-type shock waves is studied. The chemical processes responsible for the evolution of molecule abundances in the shock wave are considered in detail. The large velocity…

Astrophysics of Galaxies · Physics 2021-12-15 A. V. Nesterenok

The Odin satellite has been used to search for the 118.75-GHz line of molecular oxygen (O2)in the Galactic centre. Odin observations were performed towards the Sgr A* circumnuclear disk (CND), and the Sgr A +20 km/s and +50 km/s molecular…

We present High Sensitivity Array observation of the water megamasers of NGC 1068. We obtain absolute astrometry with 0.3 mas precision that confirms the association of the disk masers with the nuclear radio continuum source S1. The new…

Astrophysics of Galaxies · Physics 2023-08-02 Jack F. Gallimore , C. M. Violette Impellizzeri

Recently a new method to discover obscured active galactic nuclei (AGNs) by utilizing X-ray and Infrared data has been developed. We carried out a survey of H2O maser emission toward ten obscured AGNs with the Nobeyama 45-m telescope. We…