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Between 1987 and 2023 we carried out single-dish monitoring campaigns of water-maser emission at 22 GHz in the circumstellar envelopes (CSEs) of four stars: RCas, oCet, RLeo and ChiCyg. The variability in integrated flux in RCas and oCet…

星系天体物理 · 物理学 2025-06-26 Jan Brand , Dieter Engels , Alessandra Zanichelli , Sandra Etoka

An Australia Telescope Compact Array search for 22 GHz water masers towards 6.7 GHz class II methanol masers detected in the Methanol Multibeam (MMB) survey has resulted in the detection of extremely high velocity emission from one of the…

星系天体物理 · 物理学 2015-06-16 A. M. Titmarsh , S. P. Ellingsen , S. L. Breen , J. L. Caswell , M. A. Voronkov

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

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…

星系天体物理 · 物理学 2015-05-30 Jae-Han Bae , Kee-Tae Kim , So-Young Youn , Won-Ju Kim , Do-Young Byun , Hyunwoo Kang , Chung Sik Oh

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

We present results of VLBI observations of the water masers associated with IRAS 4A and IRAS 4B in the NGC 1333 star-forming region taken in four epochs over a two month period. Both objects have been classified as extremely young sources…

天体物理学 · 物理学 2009-11-13 Kevin B. Marvel , Bruce A. Wilking , Mark J Claussen , Alwyn Wootten

W75N(B) is a massive star-forming region that contains three radio continuum sources (VLA 1, VLA 2, and VLA 3), which are thought to be three massive young stellar objects at three different evolutionary stages. VLA 1 is the most evolved…

太阳与恒星天体物理 · 物理学 2014-05-28 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , C. Goddi , J. M. Torrelles , J. Cantó , S. Curiel , S. -W. Kim , J. -S. Kim

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…

天体物理学 · 物理学 2009-11-11 R. Valdettaro , F. Palla , J. Brand , R. Cesaroni

We report sub-pc-scale observations of the 321-GHz H$_2$O emission line in the radio galaxy NGC 1052. The H$_2$O line emitter size is constrained in $< 0.6$ milliarcsec distributed on the continuum core component. The brightness temperature…

We present Very Large Array (VLA) observations of H2O and OH masers, as well as radio continuum emission at 1.3 and 18 cm toward three sources previously cataloged as planetary nebulae (PNe) and in which single-dish detections of H2O masers…

We present a survey for water maser emission toward a sample of 44 low-luminosity young objects, comprising (proto-)brown dwarfs, first hydrostatic cores (FHCs), and other young stellar objects (YSOs) with bolometric luminosities lower than…

太阳与恒星天体物理 · 物理学 2017-04-26 Jose F. Gomez , Aina Palau , Lucero Uscanga , Guillermo Manjarrez , David Barrado

The present paper focuses on the high-mass star-forming region G16.59-0.05. Methods: Using the VLBA and the EVN arrays, we conducted phase-referenced observations of the three most powerful maser species in G16.59-0.05: H2O at 22.2 GHz (4…

星系天体物理 · 物理学 2015-05-18 A. Sanna , L. Moscadelli , R. Cesaroni , A. Tarchi , R. S. Furuya , C. Goddi

This paper describes the overview of the FLASHING (Finest Legacy Acquisitions of SiO-/ H$_2$O-maser Ignitions by the Nobeyama Generation) project promoted using the 45 m telescope of Nobeyama Radio Observatory, which aims to intensively…

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…

星系天体物理 · 物理学 2024-02-05 Jan Brand , Dieter Engels , Anders Winnberg

Observations of H$_2$O masers towards the post-AGB star and water fountain source OH 009.1--0.4 were made as part of HOPS (The H$_2$O southern galactic Plane Survey), with the Mopra radiotelescope. Together with followup observations using…

天体物理学 · 物理学 2008-12-11 A. J. Walsh , S. L. Breen , I. Bains , W. H. T. Vlemmings

We have conducted phase-reference multi-epoch observations of the 22.2 GHz water masers using the VLBA and multi-frequency study of the continuum emission using the VLA towards the high-mass SFR AFGL 5142. The water maser emission comes…

天体物理学 · 物理学 2009-11-11 C. Goddi , L. Moscadelli

We present Very Large Array (VLA) observations of the water maser emission towards IRAS 16552-3050. The maser emission shows a velocity spread of ~170 km/s, and a bipolar distribution with a separation between the red and blueshifted groups…

天体物理学 · 物理学 2009-11-13 Olga Suárez , J. F. Gómez , L. F. Miranda

We report on a water maser survey towards a sample of 27 planetary nebulae (PNe) using the Robledo de Chavela and Medicina single-dish antennas, as well as the Very Large Array (VLA). Two detections have been obtained: the already known…

Several radio sources have been detected in the HMSFR W75N(B), among them the massive YSOs VLA1 and VLA2 are of great interest. These are thought to be in different evolutionary stages. In particular, VLA1 is at the early stage of the…

Methanol and water masers indicate young stellar objects. They often exhibit flares, and a fraction shows periodic activity. Several mechanisms might explain this behavior but the lack of concurrent infrared (IR) data complicates to…

太阳与恒星天体物理 · 物理学 2018-08-22 B. Stecklum , A. Caratti o Garatti , K. Hodapp , H. Linz , L. Moscadelli , A. Sanna