Observation of a ring structure in SiO maser emission from late-type stars

1994 ◽  
Vol 430 ◽  
pp. L61 ◽  
Author(s):  
P. J. Diamond ◽  
A. J. Kemball ◽  
W. Junor ◽  
A. Zensus ◽  
J. Benson ◽  
...  
Keyword(s):  
Ring Structure ◽  
Late Type ◽  
Maser Emission

scholarly journals OH masers in envelopes of late type stars

1987 ◽  
Vol 122 ◽  
pp. 243-244
Author(s):  
A.M. Le Squeren ◽  
P. Sivagnanam ◽  
F. Tran Minh ◽  
M. Dennefeld ◽  
F. Foy
Keyword(s):  
Radio Telescope ◽  
Detection Rate ◽  
Point Sources ◽  
Spectral Classification ◽  
Late Type ◽  
Maser Emission ◽  
Galactic Longitude

Two studies of OH maser emission in envelopes of late type stars -miras (3) and OH/IR objects- have been performed with the Nancay radio-telescope. Mainly, the OH miras are found with thicker dust envelopes than the non OH ones. A sample of unidentified IRAS point sources selected on their colors has been observed. We have detected 46 new OH sources. The OH detection rate is a function of the galactic longitude and of the IRAS spectral classification.

scholarly journals The Galactic Distribution of OH/IR Stars

1977 ◽  
Vol 42 ◽  
pp. 399-433
Author(s):  
H.J. Habing
Keyword(s):  
Present Status ◽  
Line Emission ◽  
Microwave Line ◽  
Late Type ◽  
Maser Emission ◽  
Long Period ◽  
Ir Stars ◽  
Long Period Variables ◽  
Recent Compilation ◽  
Galactic Distribution

In 1967 Wilson and Barrett (1968, 1970) discovered that some long period variables, very red and apparently very late type stars, emit OH microwave line emission that is especially strong in the 1612 MHz line at 18 cm. At present some 65 such OH-emitting stars have been identified - for a recent compilation see Bowers and Kerr (1977, M giants) and Baudry et al. (1977, M supergiants). Several stars show maser emission in H2O and SiO as well. At this colloquium Winnberg will review the present status of our knowledge of these stars.

scholarly journals EVN and MERLIN observations of an OH maser ring and a starburst continuum in III Zw 35

2002 ◽  
Vol 206 ◽  
pp. 426-429
Author(s):  
Ylva M. Pihlström ◽  
John E. Conway ◽  
Roy S. Booth
Keyword(s):  
High Sensitivity ◽  
Ring Structure ◽  
Line Of Sight ◽  
Diffuse Emission ◽  
Maser Emission ◽  
Physical Conditions ◽  
Vlbi Observations ◽  
Geometrical Effects ◽  
Western Side ◽  
Luminous Infrared Galaxy

We report on high-sensitivity EVN and MERLIN observations of the OH maser emission and continuum in the luminous infrared galaxy III Zw 35. Earlier VLBI observations have shown two compact maser clumps containing 40%–50% of the single-dish flux. In addition to these compact masers, we detect more diffuse maser emission which lies in a clear ring structure of radius r ∼ 22 pc. The ring appears inclined to the line of sight and the compact masers occur at the tangent points. This structure suggests that the compact and diffuse masers appear different because of geometrical effects and not pumping or other physical conditions. Our observations reveal a velocity gradient along the western side of the disc which indicates rotation. The 18 cm continuum radiation is resolved into a few unresolved sources, plus more diffuse emission and is broadly consistent with emission originating in a starburst.

Time Monitoring Observations of SiO J = 2–1 and J = 3–2 Maser Emission toward Late‐Type Stars

2006 ◽  
Vol 165 (1) ◽  
pp. 360-385 ◽  
Author(s):  
Jina Kang ◽  
Se‐Hyung Cho ◽  
Hyun‐Goo Kim ◽  
Hyun‐Soo Chung ◽  
Hyo‐Ryung Kim ◽  
...  
Keyword(s):  
Late Type ◽  
Maser Emission

Monitoring of OH maser emission from late-type stars

1979 ◽  
Vol 41 ◽  
pp. 191 ◽  
Author(s):  
P. R. Jewell ◽  
J. C. Webber ◽  
L. E. Snyder ◽  
M. Elitzur
Keyword(s):  
Late Type ◽  
Maser Emission

Isotopic SiO Maser Emission from the BAaDE Survey

2017 ◽  
Vol 13 (S336) ◽  
pp. 49-52
Author(s):  
M. J Claussen ◽  
M. R. Morris ◽  
Y. M. Pihlström ◽  
L. O. Sjouwerman ◽  
Keyword(s):  
Excited States ◽  
Galactic Plane ◽  
Dynamical Evolution ◽  
Large Array ◽  
Line Profiles ◽  
Galactic Bulge ◽  
Late Type ◽  
Vibrationally Excited ◽  
Maser Emission ◽  
Very Large Array

AbstractThe Bulge Asymmetries and Dynamical Evolution (BAaDE) project aims to map the positions and velocities of up to ~20,000 late-type stars with SiO maser emission along the full Galactic plane, with a large concentration in the Galactic Bulge and inner Galaxy. Both J = 1 → 0 and J = 2 → 1 transitions using the Very Large Array (VLA) and the Atacama Large Millimeter Array (ALMA) are being observed. In the VLA observing setup, in addition to the 28SiO, v = 1 and v = 2J = 1 → 0 maser transitions, the bandwidth was wide enough to include the J = 1 → 0 transitions of the rare isotopologues of the SiO molecule in both the ground and vibrationally excited states: 29SiO, v = 0, 30SiO, v = 0, 29SiO, v = 1, and 29SiO, v = 2. Approximately 10% of the initial ~3500 targets of the project show maser emission from at least one of these lines. Some of these stars (with isotopic maser emission) show high radial velocities which implies that they are indeed in the Galactic Bulge or inner Galaxy (i.e. not foreground objects). We present line profiles, refined detection statistics, and the implications of the detection of the isotopic maser emission on pumping schemes that have been previously presented.

scholarly journals A 20-year H2O maser monitoring program with the Medicina 32-m telescope

2007 ◽  
Vol 3 (S242) ◽  
pp. 223-227 ◽  
Author(s):  
J. Brand ◽  
M. Felli ◽  
R. Cesaroni ◽  
C. Codella ◽  
G. Comoretto ◽  
...  
Keyword(s):  
Sampling Rate ◽  
Monitoring Program ◽  
Late Type ◽  
Maser Emission ◽  
Star Forming ◽  
Star Forming Regions ◽  
Vlbi Observations ◽  
Water Maser ◽  
Representative Samples

AbstractThe Arcetri/Bologna H2O maser group has been monitoring the 1.3-cm water maser emission from a sample of 43 star-forming regions (SFRs) and 22 late-type stars for about 20 years at a sampling rate of 4-5 observations each year, using the 32-m Medicina Radio Telescope (HPBW 1.′9 at 22 GHz). For the late-type stars we observe representative samples of OH/IR-stars, Mira's, semi-regular variables, and supergiants. The SFR-sample spans a large interval in FIR luminosity of the associated Young Stellar Object (YSO), from 20 L⊙ to 1.5 × 106 L⊙, and offers a unique data base for the study of the long-term (years) variability of the maser emission in regions of star formation.This presentation concerns only the masers in SFRs. The information obtained from single-dish monitoring is complementary to what is extracted from higher-resolution (VLA and VLBI) observations, and can better explore the velocity domain and the long-term variability therein.We characterize the variability of the sources in various ways and we study how it depends on the luminosity and other properties of the associated YSO and its environment.

Microwave OH maser emission in the circumstellar envelopes of late-type stars

Nature ◽  
1981 ◽  
Vol 291 (5814) ◽  
pp. 382-385 ◽  
Author(s):  
P. F. Bowers ◽  
K. J. Johnston ◽  
J. H. Spencer
Keyword(s):  
Late Type ◽  
Circumstellar Envelopes ◽  
Maser Emission
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