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We present linear and circular polarization observations of the water masers in 4 distinct regions spread over 1x2 arcseconds around the HW2 high-mass young stellar object in the Cepheus A star-forming region. We find magnetic fields…

天体物理学 · 物理学 2009-11-11 W. H. T. Vlemmings , P. J. Diamond , H. J. van Langevelde , J. M Torrelles

We demonstrate that the observed characteristics of the 5 cm OH masers in star-forming regions can be explained with the same model and the same parameters as the 18 cm and the 6 cm OH masers. In our already published study of the 18 cm and…

天体物理学 · 物理学 2009-10-31 K. G. Pavlakis , N. D. Kylafis

The star-forming region W75N hosts bright OH masers that are observed to be variable. We present observations taken in 2008 of the ground-state OH maser transitions with the Very Long Baseline Array (VLBA) and the Multi-Element Radio-Linked…

星系天体物理 · 物理学 2015-05-28 Vincent L. Fish , Malcolm Gray , W. M. Goss , A. M. S. Richards

We report the results of a search for 6.7 GHz methanol (CH3OH) maser emission in OH megamaser galaxies at 0.11<z<0.27. No detections were made in the 25 objects observed down to rms noise levels of roughly 0.6 mJy in 150 kHz channels. The…

天体物理学 · 物理学 2009-11-07 Jeremy Darling , Paul Goldsmith , Di Li , Riccardo Giovanelli

The presence of magnetic fields in O-type stars has been suspected for a long time. The discovery of such fields would explain a wide range of well documented enigmatic phenomena in massive stars, in particular cyclical wind variability, H…

天体物理学 · 物理学 2009-11-13 S. Hubrig , M. Schoeller , R. S. Schnerr , J. F. Gonzalez , R. Ignace , H. F. Henrichs

Using the Very Large Array, we have detected weak OH maser emission near the Turner-Welch protostellar source in the W3 OH region. Unlike typical interstellar OH masers, which are associated with ultra-compact HII regions, our measured…

天体物理学 · 物理学 2009-11-07 A. L. Argon , M. J. Reid , K. M. Menten

Observational evidence for the existence of cosmic magnetic fields in intergalactic space coherent over Mpc scales is presented. Using an unprecedentedly large sample of Faraday rotation measures of radio sources from the NRAO VLA Sky…

宇宙学与河外天体物理 · 物理学 2010-07-16 Jounghun Lee , Ue-Li Pen , A. Russell Taylor , Jeroen M. Stil , Caleb Sunstrum

The Large Survey Project (LSP) "MeerKAT Absorption Line Survey" (MALS) is a blind HI 21-cm and OH 18-cm absorption line survey in the L- and UHF-bands, with the primary goal to better determine the occurrence of atomic and molecular gas in…

MHD simulations show that the magnetic field can drive molecular outflows during the formation of massive protostars. The best probe to observationally measure both the morphology and the strength of this magnetic field at scales of 10-100…

太阳与恒星天体物理 · 物理学 2019-03-20 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , B. Hutawarakorn Kramer , A. Bartkiewicz

We report the discovery of variability in the OH megamaser in IRAS 21272+2514 at z=0.15. This is the first OH megamaser (OHM) observed to vary in time. The variation is broadband, spanning 0.5-1.5 MHz or 100-300 km/s in the rest frame, and…

天体物理学 · 物理学 2009-11-07 Jeremy Darling , Riccardo Giovanelli

The 1612 and 1667 MHz OH maser lines have been measured in all four Stokes parameters in 47 proto-planetary nebula (PPN) candidates. Out of 42 objects detected, 40 and 34 are 1612 and 1667 MHz emitters, respectively. The spectral extent of…

天体物理学 · 物理学 2009-11-10 M. Szymczak , E. Gerard

OH 1612 and 1667 MHz masers from the well known object OH127.8+0.0 were mon- itored in full-polarization mode over a period of 6.5 years and mapped with MERLIN at one epoch. The OH variability pattern of the star is typical of extremely…

星系天体物理 · 物理学 2013-02-11 P. Wolak , M. Szymczak , E. Gerard

We present a second epoch of observations of the 44 GHz Class I methanol maser line toward the star forming region OMC-2. The observations were carried out with the Very Large Array, and constitute one of the first successful Zeeman effect…

星系天体物理 · 物理学 2015-06-11 E. Momjian , A. P. Sarma

Full-polarization MERLIN and VLBA observations of the 1720 MHz maser emission from the OH molecule in the supernova remnant W28 are presented. Zeeman splitting (|B| \approx 0.75 mG) has been directly resolved between right- and…

天体物理学 · 物理学 2009-11-10 Ian M. Hoffman , W. M. Goss , C. L. Brogan , M. J. Claussen

We investigate the magnetic field in an intermediate-velocity filament for which the H$\alpha$ intensity in the WHAM survey correlates with excess Faraday rotation of extragalactic radio sources over the length of the filament from b ~ 20…

星系天体物理 · 物理学 2016-08-17 Jeroen M. Stil , Athena Hryhoriw

The intense line emission of OH masers is a perfect tracer of regions where new stars are born aswell as of evolved stars, shedding large amounts of processed matter into the interstellar medium. From SKA deep surveys at 18 cm, where the…

太阳与恒星天体物理 · 物理学 2015-01-29 Sandra Etoka , Dieter Engels , Hiroshi Imai , Joanne Dawson , Simon Ellingsen , Lorant Sjouwerman , Huib van Langevelde

Probing magnetic fields in high-redshift galactic systems is crucial to investigate galactic dynamics and evolution. Utilizing the rotation measure of the background quasars, we have developed a radial profile of the magnetic field in a…

星系天体物理 · 物理学 2024-09-04 Shivam Burman , Paras Sharma , Sunil Malik , Suprit Singh

The collisional pumping of OH masers in non-dissociative C-type shocks near supernova remnants is considered. The emergence of maser emission in OH lines is investigated for various shock parameters - the shock speed, the preshock gas…

星系天体物理 · 物理学 2020-10-19 A. V. Nesterenok

IRAS20126+4104 is a well studied B0.5 protostar that is surrounded by a ~1000 au Keplerian disk and is where a large-scale outflow originates. Both 6.7-GHz CH3OH masers and 22-GHz H2O masers have been detected toward this young stellar…

太阳与恒星天体物理 · 物理学 2014-03-05 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , L. Moscadelli , B. Hutawarakorn Kramer

We present the results of a search for ammonia maser emission in 119 Galactic high-mass star-forming regions (HMSFRs) known to host 22 GHz H$_2$O maser emission. Our survey has led to the discovery of non-metastable NH$_3$ inversion line…

星系天体物理 · 物理学 2024-06-19 Y. T. Yan , C. Henkel , K. M. Menten , T. L. Wilson , A. Wootten , Y. Gong , F. Wyrowski , W. Yang , A. Brunthaler , A. Kraus , B. Winkel