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Related papers: ATCA observations of SiO masers in the Galactic ce…

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The Australia Telescope Compact Array (ATCA) has been used to make the first extensive search for the class I methanol masers at 9.9 GHz. In total, 48 regions of high-mass star formation were observed. In addition to masers in W33-Met…

Astrophysics of Galaxies · Physics 2015-05-18 M. A. Voronkov , J. L. Caswell , S. P. Ellingsen , A. M. Sobolev

We conducted an SiO maser survey towards 221 O-rich AGB stars with the aim of identifying maser emission associated with the Sagittarius stellar stream. In this survey, maser emission was detected in 44 targets, of which 35 were new…

Astrophysics of Galaxies · Physics 2017-11-29 Yuanwei Wu , Noriyuki Matsunaga , Ross A. Burns , Bo Zhang

We report on a large 44 GHz ($7_0-6_1$ A$^+$) methanol (CH$_3$OH) maser survey of the Galactic Center (GC). The Karl G. Jansky Very Large Array was used to search for CH$_3$OH maser emission covering a large fraction of the region around…

Solar and Stellar Astrophysics · Physics 2016-12-07 Bridget McEwen , Loránt Sjouwerman , Ylva Pihlström

We present high spatial resolution observations of ground-state OH masers, achieved using the Australia Telescope Compact Array (ATCA). These observations were conducted towards 171 pointing centres, where OH maser candidates were…

We have searched for the SiO J=1--0 v= 1 and 2 maser lines at ~ 43 GHz in 277 2MASS/MSX/IRAS sources off the Galactic plane (|b|> 3 deg), which resulted in 119 (112 new) detections. Among the new detections, are two very faint objects with…

We present the results of an SiO maser survey for color-selected IRAS sources in the area 40 < l < 70 and |b| < 10 in the SiO J=1-0, v=1 and 2 transitions. We detected 134 out of 272 observed sources in SiO masers; 127 were new detections.…

Astrophysics · Physics 2015-06-24 Jun-ichi Nakashima , Shuji Deguchi

We report on the detection of 44 GHz Class I methanol (CH3OH) maser emission in the SgrA complex with the Expanded Very Large Array (EVLA). These EVLA observations show that the SgrA complex harbors at least four different tracers of…

Astrophysics of Galaxies · Physics 2015-05-28 Y. M. Pihlström , L. O. Sjouwerman , V. L. Fish

In the first two papers of this series, we determined the position of Sgr A* on infrared images, by aligning the positions of red giant stars with positions measured at radio wavelengths for their circumstellar SiO masers. In this paper, we…

Astrophysics · Physics 2011-02-11 M. J. Reid , K. M. Menten , S. Trippe , T. Ott , R. Genzel

The Galactic Center was observed at 8.6 mum in order to detect a mid-infrared (MIR) counterpart of Sgr A*, parallel to NIR observations. The goal was to set constraints on possible emission mechanisms.Imaging data were acquired with the…

Astrophysics · Physics 2007-05-23 R. Schoedel , A. Eckart , K. Muzic , L. Meyer , T. Viehmann , G. C. Bower

We present Very Large Array (VLA) radio interferometry observations of the 1720 MHz OH masers in the Galactic Center (GC). Most 1720 MHz OH masers arise in regions where the supernova remnant Sgr A East is interacting with the interstellar…

Astrophysics · Physics 2009-11-13 L. O. Sjouwerman , Y. M. Pihlstrom

We present a study of signatures of on-going star formation in a sample of protostellar objects with enhanced 4.5 {\mu}m emission ('green' sources) near the Galactic center. To understand how star formation in the Galactic center region…

Astrophysics of Galaxies · Physics 2015-05-27 Edward T. Chambers , Farhad Yusef-Zadeh , Doug Roberts

The study of the innermost circumstellar layers around AGB stars is crucial to understand how these envelopes are formed and evolve. The SiO maser emission occurs at a few stellar radii from the central star, providing direct information on…

Astrophysics · Physics 2009-11-13 R. Soria-Ruiz , J. Alcolea , F. Colomer , V. Bujarrabal , J. -F. Desmurs

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

We have discovered a new H$_2$CO (formaldehyde) $1_{1,0}-1_{1,1}$ 4.82966 GHz maser in Galactic Center Cloud C, G0.38+0.04. At the time of acceptance, this is the eighth region containing an H$_2$CO maser detected in the Galaxy. Cloud C is…

A new class of OH (1720 MHz) masers unaccompanied by main-line transitions have recently been discovered (Frail, Goss and Slysh 1994). These masers lie at the interface between supernova remnants (SNRs) interacting with molecular clouds. We…

Astrophysics · Physics 2007-05-23 F. Yusef-Zadeh , D. A. Roberts , G. Bower , M. Wardle

Menten, Reid, Eckart and Genzel (1997) accurately determined the position of Sgr A* on an infrared image, by aligning the infrared image with positions measured for SiO masers, associated with infrared-bright evolved stars, at radio…

Astrophysics · Physics 2009-11-07 M. J. Reid , K. M. Menten , R. Genzel , T. Ott , R. Schoedel , A. Eckart

Measuring stellar motions at the Milky Way's Galactic center (GC) provides unique insight into the dynamical processes within galactic nuclei. We present proper motion measurements for 23 SiO-maser emitting stars within 45'' of SgrA*,…

We investigate the use of 183 GHz H2O masers for characterization of the physical conditions and mass loss process in the circumstellar envelopes of evolved stars. We used APEX SEPIA Band 5 to observe the 183 GHz H2O line towards 2 Red…

We obtained, for the first time, astrometrically registered maps of the 22.2 GHz H2O and 42.8, 43.1, and 86.2 GHz SiO maser emission toward the semiregular b-type variable (SRb) R Crateris, at three epochs (2015 May 21, and 2016 January 7…

The Australia Telescope Compact Array (ATCA) has been used for high angular resolution imaging of 71 southern class I methanol maser sources quasi-simultaneously at 36 and 44 GHz. The data reveal a high level of morphological and…

Astrophysics of Galaxies · Physics 2015-06-18 M. A. Voronkov , J. L. Caswell , S. P. Ellingsen , J. A. Green , S. L. Breen