Results 131 to 140 of about 4,855 (170)

Comets and interstellar masers

Nature, 1975
RECENT advances in our understanding of the origin of the Solar System have led to renewed speculation on the origin of comets1,2. Oort3 proposed that long-period comets originate in a cometary cloud about 105 AU from the Sun and Cameron4 has suggested that this cloud has its origin in association with the primordial solar nebula.
Michael Oppenheimer
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Modelling interstellar water masers

Astrophysics and Space Science, 1995
Radiative transfer calculations for interstellar H2O have been performed using accelerated A-iteration (ALI) techniques. The results show strong maser action from known maser transitions, as well as predicting new strong maser transitions for ν > 1.5 THz. © 1995 Kluwer Academic Publishers.
Yates, JA, Gray, MD, Field, D
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Possible new interstellar masers

Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences, 1980
A collisional mechanism for the production of population inversion in the Λ -doublet sub-levels of the lowest rotational energy levels of diatomic molecules is considered. This leads to the conclusion that not only should the known celestial masers, OH and CH, be capable of exhibiting stimulated emission, but also H
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Interstellar hydroxyl and water masers and formaldehyde masers and dasars

Reports on Progress in Physics, 1974
A review of the observational data on anomalous emission by OH, H2O and H2CO molecules and on anomalous absorption by H2CO molecules. Various theories advanced to account for these data and some models of a few particular sources are discussed.
D ter Haar, M A Pelling
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Gain parameters of interstellar masers

Physics Letters A, 1972
The OH and H2O masers at the boundaries of HII regions are only partially saturated even for large solid angle. The conditions on H2O are more stringent than for OH emission.
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Interstellar masers: Then and now

1993
The large attendance at this conference, given its specialized theme, attests to the resurgence of interest in masers. Some of the reasons will be pinpointed herein. We begin with a brief history of the field and then highlight major topics of current research-masers as tracers of star-formation, outflows in star formation, magnetic fields, recently ...
Nels Anderson, Reinhard Genzel
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Maser Action in Interstellar OH

Publications of the Astronomical Society of Australia, 1968
Since 1965 we have been unravelling the curious properties of the intense 18 cm emission lines observed from OH molecules. We are still without a quantitative theory of the emission that might tie the threads together and provide guidelines for the observational work.
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The interstellar methanol masers and their environments

Science in China Series G: Physics, Mechanics and Astronomy, 2003
To promote the understanding of massive star formation processes, we have studied the 6.6 GHz methanol (CH3OH) masers and their environments—the dense cores and the outer regions of the molecular cloud. The physics of the CH3OH maser or the thermal emission formation region is studied by fitting the observational data of the 6.6 GHz 51–60A+ and the 107
Mao Ruiqing, Pei Chunchuan, Zeng Qin
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Maser action without inversion in interstellar space

Optics Communications, 1998
Abstract It is recognized that interstellar 6.7 and 12.2 GHz methanol masers toward Class II sources are associated with each other and coexist toward ultracompact HII regions. Therefore we suggest a new excitation mechanism – methanol masers without population inversion.
Hanping Liu, Jin Sun
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Masers in the Interstellar Medium

1987
The basic concepts that govern the production and propagation of maser radiation in interstellar space are introduced and discussed. Specific interstellar masers, in particular those in star forming regions, are described in some detail.
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