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相关论文: VLBI observations of the H2O gigamaser in TXS2226-…

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Context. The high intensities and narrow bandwidths exhibited by some astronomical masers make them ideal tools for studying star-forming giant molecular clouds. The water maser transition $J_{K_{-1}K_{1}}=5_{32}-4_{41}$ at 620.701 GHz can…

星系天体物理 · 物理学 2014-09-05 S. C. Jones , M. Houde , M. Harwit , M. Kidger , A. Kraus , C. McCoey , A. Marston , G. Melnick , K. M. Menten , P. Morris , D. Teyssier , V. Tolls

We present the results of a 22GHz H2O maser survey toward a new sample of AGB and post-AGB star candidates. Most of the objects are selected for the first time based on the AKARI data, which have high flux sensitivity in the mid-infrared…

太阳与恒星天体物理 · 物理学 2015-06-15 Bosco Yung , Jun-ichi Nakashima , Hiroshi Imai , Shuji Deguchi , Christian Henkel , Sun Kwok

Recently, a relationship between the water maser detection rate and far infrared (FIR) flux densities has been established as a result of two 22 GHz maser surveys in a complete sample of galaxies (Dec>-30 degree) with 100 micron flux…

宇宙学与河外天体物理 · 物理学 2015-05-13 G. Surcis , A. Tarchi , C. Henkel , J. Ott , J. Lovell , P. Castangia

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…

Context: Maser emission from the H2O molecule probes the warm, inner circumstellar envelopes of oxygen-rich red giant and supergiant stars. Multi-maser transition studies can be used to put constraints on the density and temperature of the…

天体物理学 · 物理学 2009-11-13 K. M. Menten , A. Lundgren , A. Belloche , S. Thorwirth , M. J. Reid

We report the results of a blind search for 22-GHz water masers in two regions, covering approximately half a square degree, within the giant molecular cloud associated with RCW 106. The complete search of the two regions was carried out…

Water megamaser emission at 22 GHz has proven to be a powerful tool for astrophysical studies of AGN allowing an accurate determination of the central black hole mass and of the accretion disc geometry and dynamics. However, after searches…

Maser lines from different molecular species, including water, hydroxyl, and methanol, are common observational phenomena associated with massive star forming regions. In particular, the methanol maser appears as an ideal tool to study the…

星系天体物理 · 物理学 2014-06-04 L. Olmi , E. D. Araya , P. Hofner , S. Molinari , J. Morales Ortiz , L. Moscadelli , M. Pestalozzi

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…

天体物理学 · 物理学 2008-11-26 Paul T. Kondratko , Lincoln J. Greenhill , James M. Moran

The results of high-resolution spectral-line observations of dense molecular gas are presented towards the nuclear region of the type 2 Seyfert galaxy NGC1068. MERLIN observations of the 22 GHz H2O maser were made for imaging the known…

星系天体物理 · 物理学 2024-01-03 Yoshiaki Hagiwara , Willem A. Baan , Masatoshi Imanishi , Philip Diamond

We report the results of a sensitive search for 12.2 GHz methanol maser emission towards a sample of eight high-mass star formation regions in the Large Magellanic Clouds which have been detected in other maser transitions. We detected one…

星系天体物理 · 物理学 2015-05-14 S. P. Ellingsen , S. L. Breen , J. L. Caswell , L. J. Quinn , G. A. Fuller

We investigated the ALMA science verification data of Orion KL and found a spectral signature of the vibrationally excited H2O maser line at 232.68670 GHz (nu2=1, 5,5,0-6,4,3). This line has been detected in circumstellar envelopes of…

太阳与恒星天体物理 · 物理学 2015-06-11 Tomoya Hirota , Mi Kyoung Kim , Mareki Honma

Observations of H$_2$O masers towards the post-AGB star and water fountain source OH 009.1--0.4 were made as part of HOPS (The H$_2$O southern galactic Plane Survey), with the Mopra radiotelescope. Together with followup observations using…

天体物理学 · 物理学 2008-12-11 A. J. Walsh , S. L. Breen , I. Bains , W. H. T. Vlemmings

Aim: The aim of this work is to search Seyfert 2 galaxy NGC 4945, a well-known 22 GHz water megamaser galaxy, for water (mega)maser emission at 183 GHz. Method: We used APEX SEPIA Band 5 to perform the observations. Results: We detected 183…

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…

天体物理学 · 物理学 2011-02-11 A. L. Argon , L. J. Greenhill , M. J. Reid , J. M. Moran , E. M. L. Humphreys

Analyzing archival data from different telescopes, H2O megamaser Seyfert 2s appeared to exhibit higher nuclear radio luminosities than non-masing Seyfert 2s (Zhang et al. 2012). This has been confirmed by our follow-up study on multi-band…

星系天体物理 · 物理学 2018-08-22 J. S. Zhang , Z. W. Liu , C. Henkel

We present VLBI observations of the H$_2$O maser emission towards a selection of massive young stellar objects (YSOs). In one of these sources, IRAS20126+4104, the measured proper motions confirm that the water masers spots are tracing the…

天体物理学 · 物理学 2007-05-23 M. J. Rioja , L. Moscadelli , R. Cesaroni

We report high spatial and spectral resolution measurements of masers towards R Aqr and H1-36, both of which are examples of the sub-class of symbiotic stars that contain a long-period Mira-type variable. Our observations have resulted in…

天体物理学 · 物理学 2009-10-30 Rob Ivison , J. A. Yates , P. J. Hall

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…

天体物理学 · 物理学 2009-11-13 Geumsook Park , Minho Choi

Extragalactic observations of water emission can provide valuable insights into the excitation of the interstellar medium. In addition, extragalactic megamasers are powerful probes of kinematics close to active nuclei. Therefore, it is…