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200 papers

We present an interferometric survey of the 44 GHz class I methanol maser transition toward a sample of 69 sources consisting of High Mass Protostellar Object candidates and Ultracompact (UC) H II regions. We found a 38% detection rate (16…

Astrophysics of Galaxies · Physics 2016-02-17 A. I. Gómez-Ruiz , S. E. Kurtz , E. D. Araya , P. Hofner , L. Loinard

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…

Astrophysics · Physics 2009-11-13 K. M. Menten , A. Lundgren , A. Belloche , S. Thorwirth , M. J. Reid

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

We have examined the relationship between the velocity parameters of SiO masers and the phase of the long period variable stars (LPVs) from which the masers originate. The SiO spectra from the v=1, J=1-0 (43.122 GHz; hereafter…

Solar and Stellar Astrophysics · Physics 2015-06-19 Balthasar T. Indermuehle , Gordon C. McIntosh

Outside the Milky Way, the most luminous H2O masers at 22 GHz, called 'megamasers' because of their extreme luminosity with respect to the Galactic and extragalactic H2O masers associated with star formation, are mainly detected in active…

Astrophysics of Galaxies · Physics 2020-05-20 G. Surcis , A. Tarchi , P. Castangia

We present 86 GHz (v = 1, J = 2 -1) SiO maser line observations with the IRAM 30-m telescope of a sample of 441 late-type stars in the Inner Galaxy (-4 degr < l < +30 degr). These stars were selected on basis of their infrared magnitudes…

Astrophysics · Physics 2009-11-07 M. Messineo , H. J. Habing , L. O. Sjouwerman , A. Omont , K. M. Menten

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…

Astrophysics of Galaxies · Physics 2024-03-14 Xu-Jia Ouyang , Yong Zhang , Juan Li , Jun-ichi Nakashima , Xi Chen , Hai-Hua Qiao

We have conducted multi-epoch EVN observations of the 22.2 GHz water masers towards four high-mass star forming regions (Sh 2-255 IR, IRAS 23139+5939, WB89-234, and OMC2). The (three) observing epochs span a time range of 6 months. In each…

Astrophysics · Physics 2016-08-30 C. Goddi , L. Moscadelli , W. Alef , A. Tarchi , J. Brand , M. Pani

We present results on a search for 86.243 GHz SiO (J = 2 -- 1, v = 1) maser emission toward 67 OH/IR stars located near the Galactic Centre. We detected 32 spectral peaks, of which 28 correspond to SiO maser lines arising from the envelopes…

Astrophysics of Galaxies · Physics 2020-07-08 M. Messineo , L. O. Sjouwerman , H. J. Habing , A. Omont

There is an approximately 60% detection rate for 1612 MHz masers in association with red, color-selected IRAS sources, though few are detected from the bluer circumstellar shells of Mira variables. On the other hand and complementarily,…

Astrophysics · Physics 2009-10-30 B. M. Lewis

We present our past and current long-term monitoring program of water masers in the circumstellar envelopes of evolved stars, augmented by occasional interferometric observations. Using as example the Mira-variable U Her, we identify three…

Astrophysics of Galaxies · Physics 2024-02-05 Jan Brand , Dieter Engels , Anders Winnberg

Studying stars that are located off the Galactic plane is important for understanding the formation history of the Milky Way. We searched for SiO masers toward off-plane O-rich asymptotic giant branch (AGB) stars from the catalog presented…

Astrophysics of Galaxies · Physics 2023-10-23 Wenjin Yang , Yuanwei Wu , Yan Gong , Nicolas Mauron , Bo Zhang , Karl M. Menten , Xiaofeng Mai , Dejian Liu , Juan Li , Jingjing Li

We present ATCA observations of the H2O maser line and radio continuum at 18.0GHz and 22.8GHz, toward a sample of 192 massive star forming regions containing several clumps already imaged at 1.2mm. The main aim of this study is to…

Astrophysics of Galaxies · Physics 2015-06-12 A. Sanchez-Monge , M. T. Beltran , R. Cesaroni , F. Fontani , J. Brand , S. Molinari , L. Testi , M. Burton

SiO maser emission occurs in the extended atmosphere of evolved stars and can be studied at high angular resolution. Very long baseline interferometry (VLBI) observations of Mira variables indicate that SiO masers are significantly linearly…

Solar and Stellar Astrophysics · Physics 2015-05-30 N. Amiri , W. H. T. Vlemmings , A. J. Kemball , H. J. van Langevelde

RV variable stars are important in astrophysics. The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectroscopic survey has provided ~ 6.5 million stellar spectra in its Data Release 4 (DR4). During the survey, ~ 4.7…

Data for a number of OH maser lines have been collected from surveys. The posi- tions are compared to recent mid-infrared (MIR) surveys such as Spitzer-GLIMPSE and WISE, restricting the comparison to point sources. The colors and…

Astrophysics of Galaxies · Physics 2014-04-21 Haihua Qiao , Juan Li , Zhiqiang Shen , Xi Chen , Xingwu Zheng

A sample of 30 H2O extra-galactic maser galaxies with their published HCN(J=1-0) and HCO+(J=1-0) observations has been compiled to investigate the dense gas correlation with H2O maser emission. Our sample number exceeds the size of the…

Astrophysics of Galaxies · Physics 2020-10-14 A. Farhan , E. N. Ercan , F. Tombesi

We present a millimetre molecular line survey of seven high mass loss rate carbon stars in both the northern and southern skies. A total of 196 emission lines (47 transitions) from 24 molecular species were detected. The observed CO…

Astrophysics · Physics 2009-11-07 P. M. Woods , F. L. Schoeier , L. -A. Nyman , H. Olofsson

The 25 years following the serendipitous discovery of megamasers have seen tremendous progress in the study of luminous extragalactic H$_2$O emission. Single-dish monitoring and high resolution interferometry have been used to identify…

Astrophysics · Physics 2009-11-10 C. Henkel , J. A. Braatz , A. Tarchi , A. B. Peck , N. M. Nagar , L. J. Greenhill , M. Wang , Y. Hagiwara

We present new observations of C-band continuum emission and masers to assess high-mass ($>$8 $M_\odot$) star formation at early evolutionary phases in the inner 200 pc of the Central Molecular Zone (CMZ) of the Galaxy. The continuum…