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Flares of the H2O maser in W31(2)
- Source :
- Astronomy Letters. 31:315-326
- Publication Year :
- 2005
- Publisher :
- Pleiades Publishing Ltd, 2005.
-
Abstract
- We analyze our monitoring data for the water-vapor maser in the source W31(2), associated with a region of vigorous star formation, a cluster of OB stars. The monitoring was performed with the 22-m radio telescope at Pushchino Radio Astronomy Observatory during 1981–2004. The variability of the H2O maser in W31(2) was found to be cyclic, with a mean period of 1.9 yr. Two flares were most intense (superflares): in 1985–1986 and 1998–1999. In each activity cycle, we observed up to several short flares, subpeaks. The fluxes of many emission features during the flares were correlated. We also observed successive activation of individual emission features in order of increasing or decreasing radial velocity, suggesting an ordered structure and, hence, a radial-velocity gradient of the medium. There is a clear correlation of the emission peaks of the main components in the spectra at radial velocities of −1.7, −1.3, 0.5, and 1.3 km s−1 with activity cycles and of the emission at VLSR < −8 km s−1 with short flares. During the superflares, the emission in the low-velocity part of the H2O spectrum and a number of other phenomena related to coherent maser-emission properties were suppressed. The maser spots are assumed to form a compact structure, to have a common pumping source, and to be associated with an accretion flow onto the cluster of OB stars.
- Subjects :
- Physics
Accretion (meteorology)
Star formation
Astrophysics::High Energy Astrophysical Phenomena
Astronomy
Astronomy and Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
law.invention
Radio telescope
Radial velocity
Stars
Space and Planetary Science
law
Astrophysics::Solar and Stellar Astrophysics
OH/IR star
Maser
Astrophysics::Galaxy Astrophysics
Superflare
Subjects
Details
- ISSN :
- 15626873 and 10637737
- Volume :
- 31
- Database :
- OpenAIRE
- Journal :
- Astronomy Letters
- Accession number :
- edsair.doi...........14031cde3bef7eba8d5df50d5a58272a
- Full Text :
- https://doi.org/10.1134/1.1922530