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相关论文: OH and H2O maser variations in W33B

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The IRAS source, 19312+1950, exhibits SiO maser emission, which is predominantly detected in evolved stars enshrouded by a cold molecular envelope. In fact, the mojority of the observational properties of IRAS 19312+1950 is consistent with…

太阳与恒星天体物理 · 物理学 2015-05-20 Jun-ichi Nakashima , Shuji Deguchi , Hiroshi Imai , Athol Kemball , B. M. Lewis

Water fountain objects are generally defined as "evolved stars with low to intermediate initial mass accompanied by high-velocity molecular jets detectable in the 22.235 GHz H$_2$O maser line". They are the key objects of understanding the…

星系天体物理 · 物理学 2024-03-14 Xu-Jia Ouyang , Yong Zhang , Juan Li , Jun-ichi Nakashima , Xi Chen , Hai-Hua Qiao

We present the results of a monitoring campaign using the KAT-7 and HartRAO 26m telescopes, of hydroxyl, methanol and water vapour masers associated with the high-mass star forming region G9.62+0.20E. Periodic flaring of the main line…

太阳与恒星天体物理 · 物理学 2019-03-20 S. Goedhart , R. van Rooyen , D. J. van der Walt , J. P. Maswanganye , A. Sanna , G. C. MacLeod , S. P. van den Heever

Recent studies of methanol and ground-state OH masers at very high spectral resolution have shed new light on small-scale maser processes. The nearby source W3(OH), which contains numerous bright masers in several different transitions,…

天体物理学 · 物理学 2009-11-13 Vincent L. Fish , Loránt O. Sjouwerman

A sample of J-type carbon stars was searched for OH maser emission. The new detection of three OH lines towards two silicate carbon stars is reported. In V778 Cyg, previously known as the main-lines (1665 and 1667 MHz) maser source, the…

天体物理学 · 物理学 2016-01-27 M. Szymczak , R. Szczerba , P. S. Chen

We report dual-frequency very long baseline interferometry (VLBI) observations at 22 and 43 GHz toward the nucleus of a nearby radio galaxy NGC 4261. In particular, we present a VLBI image of the 22 GHz H2O maser line and its location in…

星系天体物理 · 物理学 2023-05-31 Satoko Sawada-Satoh , Nozomu Kawakatu , Kotaro Niinuma , Seiji Kameno

The polarized emission of astrophysical masers, especially OH and methanol lines, is an effective tool to study the magnetic field in high-mass star-forming regions. The magnetic field strength measurement via the Zeeman effect of OH maser…

星系天体物理 · 物理学 2025-08-21 A. Kobak , G. Surcis , A. Bartkiewicz , W. H. T. Vlemmings , M. Szymczak

22 GHz water vapor `kilomaser' emission is reported from the central region of the Whirlpool galaxy M 51 (NGC 5194). The red-shifted spectral features (Vlsr ~ 560 km/s), flaring during most of the year 2000, originate from a spatially…

天体物理学 · 物理学 2016-08-30 Yoshiaki Hagiwara , Christian Henkel , Karl. M. Menten , Naomasa Nakai

OH(1720 MHz) masers are created by the interaction of supernova remnants with molecular clouds. These masers are pumped by collisions in warm, shocked molecular gas with OH column densities in the range 10^{16}--10^{17} cm^{-2}. Excitation…

星系天体物理 · 物理学 2015-06-04 Mark Wardle , Korinne McDonnell

We present observations of far-infrared (50-200 micron) OH and H2O emission of the disk around the Herbig Ae star HD 163296 obtained with Herschel/PACS in the context of the DIGIT key program. In addition to strong [OI] emission, a number…

太阳与恒星天体物理 · 物理学 2015-06-05 D. Fedele , S. Bruderer , E. F. van Dishoeck , G. J. Herczeg , N. J. Evans , J. Bouwman , Th. Henning , J. Green

We report the results of a full-Stokes survey of all four 18 cm OH lines in 77 OH megamasers (OHMs) using the Arecibo Observatory. This is the first survey of OHMs that included observations of the OH satellite lines; only 4 of the 77 OHMs…

宇宙学与河外天体物理 · 物理学 2013-08-16 James McBride , Carl Heiles , Moshe Elitzur

We have used the Australia Telescope Compact Array (ATCA) to make a sensitive (5-$\sigma$ $\simeq$ 100 mJy) search for maser emission from the 4765-MHz $^2\Pi_{1/2}$ F=1$\to$0 transition of OH. Fifty five star formation regions were…

天体物理学 · 物理学 2009-11-07 R. Dodson , S. P. Ellingsen , M. A. Voronkov

H2O (22 GHz) and SiO masers (43, 86, 129 GHz) in the bipolar proto-planetary nebula OH231.8+4.2 were simultaneously monitored using the 21-m antennas of the Korean VLBI Network in 2009-2015. Both species exhibit periodic flux variations…

太阳与恒星天体物理 · 物理学 2019-07-04 J. Kim , S. -H. Cho , V. Bujarrabal , H. Imai , R. Dodson , D. -H. Yoon , B. Zhang

OH is a key species in the water chemistry of star-forming regions, because its presence is tightly related to the formation and destruction of water. This paper presents OH observations from 23 low- and intermediate-mass young stellar…

NGC7538 is a complex massive star-forming region. The region is composed of several radio continuum sources, one of which is IRS1, a high-mass protostar, from which a 0.3 pc molecular bipolar outflow was detected. Several maser species have…

太阳与恒星天体物理 · 物理学 2015-05-28 G. Surcis , W. H. T. Vlemmings , R. M. Torres , H. J. van Langevelde , B. Hutawarakorn Kramer

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…

星系天体物理 · 物理学 2015-05-13 J. -F. Desmurs , C. Codella , J. Santiago-Garcia , M. Tafalla , R. Bachiller

Full polarization measurements of 1665 and 1667-MHz OH masers at 261 sites of massive star formation have been made with the Parkes radio telescope. Here we present the resulting spectra for 157 southern sources, complementing our…

星系天体物理 · 物理学 2014-02-13 J. L. Caswell , J. A. Green , C. J. Phillips

We have observed the OH 1612-MHz maser emission towards the proto-planetary nebula candidate OH17.7-2.0 that underwent a very strong and unusual outburst in 2003. Phase-referencing data were obtained with the EVN in order to localize the…

天体物理学 · 物理学 2009-04-16 M. Szymczak , A. Bartkiewicz , E. Gerard

The W28 supernova remnant is an excellent prototype for observing shocked gas resulting from the interaction of supernova remnants (SNRs) and adjacent molecular clouds (MCs). We present two new signatures of shocked molecular gas in this…

天体物理学 · 物理学 2016-08-30 F. Yusef-Zadeh , M. Wardle , D. A. Roberts

Astrophysical masers are widely used in star formation studies. In particular, they are valuable in investigations of high-mass star-forming regions that are difficult to observe at optical frequencies. We used multi-transition data to…

太阳与恒星天体物理 · 物理学 2025-03-17 A. Kobak , A. Bartkiewicz , K. L. J. Rygl , A. M. S. Richards , M. Szymczak , P. Wolak