Spectral observations of OH and water maser sources at the Crimean Astrophysical Observatory with the RT-22 radio telescope

2006 ◽  
Vol 25 (5-6) ◽  
pp. 379-384 ◽  
Author(s):  
L. N. Volvach ◽  
A. E. Volvach ◽  
I. D. Strepka
Keyword(s):  
Radio Telescope ◽  
Crimean Astrophysical Observatory ◽  
Maser Sources ◽  
Water Maser

scholarly journals Flares of radio line emission H2O in Ori A and W49N

1990 ◽  
Vol 137 ◽  
pp. 275-278
Author(s):  
I.V. Gosachinskij ◽  
N.A. Yudaeva ◽  
R.A. Kandalian ◽  
F.S. Nazaretian ◽  
V.A. Sanamian
Keyword(s):  
Radio Telescope ◽  
Line Emission ◽  
Light Curves ◽  
Time Behaviour ◽  
Velocity Range ◽  
Radio Line ◽  
Total Luminosity ◽  
First Time ◽  
Maser Sources ◽  
Water Maser

The results of observations of H2O maser sources Ori A and W49N at 1.35cm made the RATAN-600 radio telescope from June 1981 till December 1988 are presented. The light curves of these sources showed several outbursts. Duration of the strongest outbursts for the Ori A and W49N are approximately 1 and 1.5yr respectively. The maximum of the total luminosity (assuming isotropic emission) of these sources for the velocity range ±8km.s-1 is egual to 1×1047 ph.s-1 and 2×1049 ph.s-1 respectively. The time behaviour of the water maser source in W49N during more than 7yr is monitored for the first time.

scholarly journals Intermittent maser flare around the high-mass young stellar object G353.273+0.641

2012 ◽  
Vol 8 (S287) ◽  
pp. 98-102
Author(s):  
Kazuhito Motogi ◽  
Kazuo Sorai ◽  
Kenta Fujisawa ◽  
Koichiro Sugiyama ◽  
Mareki Honma
Keyword(s):  
Light Curve ◽  
Small Area ◽  
Linear Acceleration ◽  
High Mass ◽  
Velocity Range ◽  
Time Resolved ◽  
Almost All ◽  
Maser Sources ◽  
Water Maser

AbstractThe water maser site associated with G353.273+0.641 is classified as a dominant blueshifted H2O maser, which shows an extremely wide velocity range (± 100 km s−1) with almost all flux concentrated in the highly blueshifted emission. The previous study has proposed that this peculiar H2O maser site is excited by a pole-on jet from high mass protostellar object. We report on the monitoring of 22-GHz H2O maser emission from G353.273+0.641 with the VLBI Exploration of Radio Astrometry (VERA) and the Tomakamai 11-m radio telescope. Our VLBI imaging has shown that all maser features are distributed within a very small area of 200 × 200 au2, in spite of the wide velocity range (> 100 km s−1). The light curve obtained by weekly single-dish monitoring shows notably intermittent variation. We have detected three maser flares during three years. Frequent VLBI monitoring has revealed that these flare activities have been accompanied by a significant change of the maser alignments. We have also detected synchronized linear acceleration (−5 km s−1yr−1) of two isolated velocity components, suggesting a lower-limit momentum rate of 10−3 M⊙ km s−1yr−1 for the maser acceleration. All our results support the previously proposed pole-on jet scenario, and finally, a radio jet itself has been detected in our follow-up ATCA observation. If highly intermittent maser flares directly reflect episodic jet-launchings, G353.273+0.641 and similar dominant blueshifted water maser sources can be suitable targets for a time-resolved study of high mass protostellar jet.

VERA Single Dish Observations

2017 ◽  
Vol 13 (S336) ◽  
pp. 307-308
Author(s):  
Kazuyoshi Sunada ◽  
Takumi Nagayama ◽  
Aya Yamauchi ◽  
Tomoya Hirota ◽  
Katsunori M. Shibata ◽  
...  
Keyword(s):  
Maser Sources ◽  
Bright Source ◽  
Water Maser

AbstractWe will report the activities of the VERA single-dish observations. We are carrying out single-dish observations with two purposes. The first purpose is the monitoring of known H2O maser sources. At present, we are carrying out monitoring observations for 312 H2O maser sources at intervals of two months. The second purpose is the search for new water maser sources. We selected 901 target sources from the AKARI FIS Bright Source Catalogue. We found 61 new H2O maser sources.

scholarly journals Masers as probes of proto-planetary discs

2004 ◽  
Vol 202 ◽  
pp. 362-364
Author(s):  
A.M.S. Richards ◽  
R. J. Cohen ◽  
M. Crocker ◽  
E. E. Lekht ◽  
V. Samodourov ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Radio Telescope ◽  
Keplerian Orbit ◽  
Proper Motions ◽  
Central Mass ◽  
Maser Emission ◽  
Star Forming ◽  
Star Forming Regions ◽  
Velocity Variations ◽  
Water Maser

Water maser emission from star forming regions has been monitored for several decades using the Puschino radio telescope, showing radial velocity variations consistent with material in Keplerian orbit around protostars. MERLIN and the EVN are now being used to image the 22 GHz emission on au scales and measure proper motions. This will distinguish discs from outflows, and provide an estimate of the central mass and possibly orbiting condensations.

scholarly journals Proper Motions and Distances of Water Maser Complexes

1984 ◽  
Vol 110 ◽  
pp. 335-338
Author(s):  
M. H. Schneps ◽  
M. J. Reid ◽  
J. M. Moran ◽  
R. Genzel ◽  
D. Downes ◽  
...  
Keyword(s):  
Spectral Line ◽  
Galactic Center ◽  
Three Dimensional ◽  
Proper Motions ◽  
Preliminary Results ◽  
First Results ◽  
Maser Sources ◽  
Water Maser

We report preliminary results of a long term spectral line VLBI experiment to observe internal proper motions of water maser sources in the vicinity of newly formed stars. This technique yields a picture of the three-dimensional kinematics of the region and a measure of the distance to the source. First results from the galactic center source SGR B2 are presented.

scholarly journals Monitoring of extragalactic water masers with the MPIfR 100-m telescope

2002 ◽  
Vol 206 ◽  
pp. 392-395
Author(s):  
Yoshiaki Hagiwara ◽  
Christian Henkel ◽  
William A. Sherwood
Keyword(s):  
Radio Telescope ◽  
Radio Galaxy ◽  
Maser Emission ◽  
Monitoring Period ◽  
Water Masers ◽  
Water Maser

We present single-dish monitoring of the 22 GHz water maser lines from the Seyfert 2 galaxies NGC 3079, M51(NGC 5194), NGC 5793, and the radio galaxy NGC 315 with the Effelsberg 100-m radio telescope. During the monitoring period of 1995 − 2001, the H2O masers flared in M51 and NGC 5793, while maser emission from NGC 315 was not detected in 1996 and 2000. During 2000, we discovered new red-shifted velocity features in NGC 3079 and blue-shifted features in M51. These velocity components are crucial to model the distribution of maser emission in each galaxy.

scholarly journals 22 GHz Water Maser Survey of the Xinjiang Astronomical Observatory

2012 ◽  
Vol 8 (S287) ◽  
pp. 296-297
Author(s):  
Jian-jun Zhou ◽  
Jarken Esimbek ◽  
Gang Wu
Keyword(s):  
Galactic Plane ◽  
Astronomical Observatory ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Gas Kinematics ◽  
Star Forming Regions ◽  
Water Masers ◽  
Maser Sources ◽  
Water Maser

AbstractWater masers are good tracers of high-mass star-forming regions. Water maser VLBI observations provide a good probe for studying high-mass star formation and galactic structure. We plan to make a blind survey toward the northern Galactic plane in future years using the 25 m radio telescope of the Xinjiang Astronomical Observatory. We will select some water maser sources discovered in the survey and perform high resolution observations to study the gas kinematics close to high-mass protostars.

scholarly journals Parallax measurements of water maser sources beyond 5 kpc with VERA

2007 ◽  
Author(s):  
Mareki Honma ◽  
Takeshi Bushimata ◽  
Yoon Kyung Choi ◽  
Tomoya Hirota ◽  
Kenzaburo Iwadate ◽  
...  
Keyword(s):  
Maser Sources ◽  
Water Maser

scholarly journals Observations of variability of H2O Maser sources associated with star formation regions

1991 ◽  
Vol 147 ◽  
pp. 482-484
Author(s):  
M. I. Pashchenko ◽  
E. E. Lekht ◽  
I. I. Berulis ◽  
R. L. Sorochenko
Keyword(s):  
Star Formation ◽  
Flux Density ◽  
Time Variability ◽  
Line Profiles ◽  
Maser Emission ◽  
Outstanding Feature ◽  
Star Formation Regions ◽  
Maser Sources ◽  
Water Maser

An outstanding feature of the water maser emission from star formation regions is the strong time variability, which was recognised soon after the discovery of interstellar H2O masers. It is likely that the observed considerable variations of the H2O line profiles as well as of the flux density reflect the disturbancies in the protostellar nebule probably associated with the outflow from the newly formed stars.

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