Results 111 to 120 of about 154 (145)

Masers, Lasers and the Interstellar Medium

Astrophysics and Space Science, 1997
This paper discusses recent results obtained by myself and my colleagues in three domains of astrophysics: interstellar supersonic turbulence, circumstellar disks, and natural masers and lasers. S.A. Kaplan, S.B. Pikelner, and I.S. Shklovskii were among those who, 30-40 years ago, laid the foundation of these domains.
exaly   +2 more sources

A Radiation Mechanism for Interstellar Methanol 6.7GHz Masers

Astrophysics and Space Science, 1997
All interstellar methanol maser sources can be divided into two classes. Their spectra are distinctive. In particular, the prominent Class II maser transitions, 6.7GHz and 12.2GHz lines show enhanced absorption toward Class I sources. We notice that the 6.7 and 12.2GHz methanol masers toward Class II sources are associated with each other and coexist ...
Liu Hanping, Sun Jin
exaly   +2 more sources

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
openaire   +2 more sources

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
openaire   +2 more sources

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
openaire   +1 more source

Possible new interstellar masers

Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences, 1980
Abstract 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 F+, HC1 ...
Elizabeth Gold, R. E. Hammersley, W. G. Richards   +2 more
openaire   +1 more source

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.
openaire   +1 more source

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.
openaire   +1 more source

Radiative Stability of the Interstellar Masers

Publications of the Astronomical Society of Japan, 1974
Abstract The stability of the radiation field in the interstellar masers is studied using the radiative transfer equations and the rate equations. The model used is the cylindrical homogeneous maser with steady pumping. It is found that the maser whose optical depth is larger than a critical value is unstable and has no stable steady ...
openaire   +1 more source

Ammonia masers in the interstellar medium

1993
Since 1986, 10 ammonia masers have been found. Most of these are found in the sources W51D, W51e1/e2, NGC7538, DR21 and W33. Among them are a few masers or maser candidates, arising from metastable inversion lines. There are many more masers arising from non-metastable inversion lines. The most outstanding is intense maser emission from the (J,K)=(9,6)
T. L. Wilson, P. Schilke
openaire   +1 more source