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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

A survey of the inner 8$^\circ \times 1^\circ$ of the Galactic plane toward the Galactic center has been carried out at the 1720 MHz transition of OH molecule using the VLA in its D configuration with a resolution of…

Astrophysics · Physics 2009-05-20 F. Yusef-Zadeh , W. M. Goss , D. A. Roberts , B. Robinson , D. A. Frail

We present high spatial resolution observations of ground-state OH masers achieved with the Australia Telescope Compact Array (ATCA). These observations targeted 253 pointing centres containing OH maser candidates at all four ground-state…

We report full polarimetric VLBA observations of water masers towards the Turner-Welch Object in the W3(OH) high-mass star forming complex. This object drives a synchrotron jet, which is quite exceptional for a high-mass protostar, and is…

Astrophysics of Galaxies · Physics 2016-12-28 C. Goddi , G. Surcis , L. Moscadelli , H. Imai , W. H. T. Vlemmings , H. J. van Langevelde , A. Sanna

The active star-forming region W33B is a source of OH and H2O maser emission located in distinct zones around the central object. The aim was to obtain the complete Stokes pattern of polarised OH maser emission, to trace its variability and…

Astrophysics of Galaxies · Physics 2015-02-25 P. Colom , E. E. Lekht , M. I. Pashchenko , G. M. Rudnitskij

We present combined observations of the NH3 (J,K) = (1,1) and (2,2) inversion transitions towards OMC1 in Orion A obtained by the Karl G. Jansky Very Large Array (VLA) and the 100 m Robert C. Byrd Green Bank Telescope (GBT). With an angular…

We present a comprehensive view of the W51B HII region complex and the W51C supernova remnant (SNR) using new radio observations from the VLA, VLBA, MERLIN, JCMT, and CSO along with archival data from Spitzer, ROSAT, ASCA, and Chandra. Our…

We present the results of the first dedicated survey for 22 GHz H$_2$O maser emission in dwarf galaxies outside of the local group, with the aim of discovering disc masers. Studies of disc masers yield accurate and precise measurements of…

Astrophysics of Galaxies · Physics 2020-10-21 M. J. Rosenthal , I. Zaw

We present deep GMRT OH and WSRT HI absorption spectra of the $z = 0.6846$ gravitational lens toward B0218+357. Both the 1665 MHz and 1667 MHz OH lines are clearly detected for the first time while a new wide absorption component was…

Astrophysics · Physics 2009-11-10 N. Kanekar , J. N. Chengalur , A. G. de Bruyn , D. Narasimha

We report on Green Bank Telescope 23.87 GHz NH$_3$(3,3), emission observations in five supernova remnants interacting with molecular clouds (G1.4$-$0.1, IC443, W44, W51C, and G5.7$-$0.0). The observations show a clumpy gas density…

Astrophysics of Galaxies · Physics 2016-08-17 Bridget McEwen , Ylva Pihlström , Loránt Sjouwerman

Magnetic fields can play an important role in stellar evolution. Among white dwarfs, the most common stellar remnant, the fraction of magnetic systems is more than 20 per cent. The origin of magnetic fields in white dwarfs, which show…

Solar and Stellar Astrophysics · Physics 2022-04-27 Ingrid Pelisoli , M. Dorsch , U. Heber , B. Gänsicke , S. Geier , T. Kupfer , P. Németh , S. Scaringi , V. Schaffenroth

Magnetic fields likely play an important role in star formation, but the number of directly measured magnetic field strengths remains scarce. We observed the 38.3 and 38.5 GHz Class II methanol (CH$_3$OH) maser lines toward the high mass…

Astrophysics of Galaxies · Physics 2023-09-29 E. Momjian , A. P. Sarma

Magnetic fields have only recently been included in theoretical simulations of high-mass star formation. The simulations show that magnetic fields play an important role in the formation and dynamics of molecular outflows. Masers, in…

Solar and Stellar Astrophysics · Physics 2015-06-16 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , B. Hutawarakorn Kramer , L. H. Quiroga-Nunez

We report a multi-epoch, simultaneous 22 GHz H2O and 44 GHz class I CH3OH maser line survey towards 180 intermediate-mass young stellar objects, including 14 Class 0, 19 Class I objects, and 147 Herbig Ae/Be stars. We detected H2O and CH3OH…

Astrophysics of Galaxies · Physics 2015-05-30 Jae-Han Bae , Kee-Tae Kim , So-Young Youn , Won-Ju Kim , Do-Young Byun , Hyunwoo Kang , Chung Sik Oh

Our analysis of a VLBA 12-hour synthesis observations of the OH masers in W49N has provided detailed high angular-resolution images of the maser sources, at 1612, 1665 and 1667 MHz. The images, of several dozens of spots, reveal anisotropic…

Astrophysics of Galaxies · Physics 2015-06-04 Avinash A. Deshpande , W. M. Goss , J. E. Mendoza-Torres

(Edited for length) The Zeeman effect is the only observational technique available to measure directly the strength of magnetic fields in regions of star formation. We review the physics of the Zeeman effect and its practical use in both…

Astrophysics of Galaxies · Physics 2019-11-15 Richard M. Crutcher , Athol J. Kemball

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 the first variability study of the 1720 MHz OH masers located in the Galactic Center. Most of these masers are associated with the interaction between the supernova remnant SgrAEast and the interstellar medium, but a few masers…

Astrophysics of Galaxies · Physics 2015-05-28 Y. M. Pihlström , L. O. Sjouwerman , R. A. Mesler

High mass stars play an important role in the Interstellar Medium, but much remains to be known about their formation. Class I methanol masers may be unique tracers of an early stage of high mass star formation, and a better understanding…

Astrophysics of Galaxies · Physics 2022-05-18 Nycole Wenner , A. P. Sarma , E. Momjian

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…

Astrophysics of Galaxies · Physics 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