# MASER OBSERVATIONS OF WESTERLUND 1 AND COMPREHENSIVE CONSIDERATIONS ON MASER PROPERTIES OF RED SUPERGIANTS ASSOCIATED WITH MASSIVE CLUSTERS

@article{Fok2012MASEROO,
title={MASER OBSERVATIONS OF WESTERLUND 1 AND COMPREHENSIVE CONSIDERATIONS ON MASER PROPERTIES OF RED SUPERGIANTS ASSOCIATED WITH MASSIVE CLUSTERS},
author={Thomas K. T. Fok and J. Nakashima and B. Yung and C. Hsia and Shuji Deguchi U. of Hong Kong and Nobeyama Solar Radio Observatory},
journal={The Astrophysical Journal},
year={2012},
volume={760},
pages={65}
}
We report the results of Australia Telescope Compact Array observations of the Westerlund 1 (Wd1) region in the SiO v = 1, J = 1-0, and H2O 616-523 maser lines, and we also report the analysis of maser properties of red supergiants (RSGs) associated with six massive clusters including Wd1. The primary purpose of this research is to explore possibilities of using maser emission for investigating the nature of massive clusters and associated RSGs. The SiO v = 1, J = 1-0, and H2O 616-523 maser… Expand

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#### References

SHOWING 1-10 OF 62 REFERENCES
SiO maser emission from red supergiants across the Galaxy - I. Targets in massive star clusters
• Physics
• 2012
Aims. Red supergiants (RSGs) are among the most luminous of all stars, easily detectable in external galaxies, and may ideally serve as kinematic tracers of Galactic structure. Some RSGs areExpand
SiO and H2O Maser Observations of Red Supergiants in Star Clusters Embedded in the Galactic Disk
• Physics
• 2010
We present the result of radio observations of red supergiants in the star cluster, Stephenson's #2, and candidates for red supergiants in the star clusters, Mercer et al. (2005)'s #4, #8, and #13,Expand
Kashima 34-m Water Maser Survey of Late-Type Stars
• Physics
• 2001
This paper presents new results of a water maser survey of late-type stellar objects at 22.235GHz with the Kashima 34-m radio telescope. We have detected 179 out of 643 observed sources, including 32Expand
Westerlund 1: bound or unbound?
• Physics
• 2009
The Galactic open cluster Westerlund 1 (Wd 1) represents the ideal local template for extragalactic young massive star clusters, because it is currently the only nearby young cluster with a mass ofExpand
HIGH-RESOLUTION VLBA OBSERVATIONS OF THREE 7 mm SiO MASERS TOWARD VX Sgr AT FIVE EPOCHS
• Physics
• 2012
VX Sgr is a red supergiant at an adopted distance of 1.6 kpc with intense 43 GHz SiO maser emission. In this paper, we present the high-resolution very long baseline interferometry (VLBI)Expand
The Cool Supergiant Population of the Massive Young Star Cluster RSGC1
We present new high-resolution near-IR spectroscopy and OH maser observations to investigate the population of cool luminous stars of the young massive Galactic cluster RSGC1. Using the 2.293 μm COExpand
SiO masers in a scutum massive star cluster of red supergiants
• Physics
• 2006
We have detected five objects toward a Scutum massive star cluster of red supergiants in the SiO J = 1-0, v = 1 or v = 2 transitions. The radial velocity data indicate that four of the detections areExpand
DISTANCE AND KINEMATICS OF THE RED HYPERGIANT VY CMa: VERY LONG BASELINE ARRAY AND VERY LARGE ARRAY ASTROMETRY
• Physics
• 2012
We report astrometric results of phase-referencing very long baseline interferometry observations of 43 GHz SiO maser emission toward the red hypergiant VY Canis Majoris (VY CMa) using the Very LongExpand
DISTANCE AND PROPER MOTION MEASUREMENT OF THE RED SUPERGIANT, S PERSEI, WITH VLBI H2O MASER ASTROMETRY
• Physics
• 2010
We have conducted Very Long Baseline Array phase-referencing monitoring of H2O masers around the red supergiant, S Persei, for six years. We have fitted maser motions to a simple expanding-shellExpand
Outburst OH maser activity in the envelopes of S Persei and VX Sagittarii
• Physics
• 2010
Context. OH masers from the envelopes of M-type supergiants show a significant degree of polarization, implying magnetic fields of a few mG. Nothing is known about the temporal characteristics of theExpand