Excitation of millimeter and submillimeter water masers

Journal Article · Fri Feb 01 04:00:00 EST 1991 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169685· OSTI ID:5758055

Neufeld, D A; Melnick, G J ^[1]

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1. California Univ., Berkeley (USA) Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA)

The excitation of maser emission in millimeter and submillimeter transitions of interstellar and circumstellar water is considered. An escape probability method is used to determine the equilibrium populations in 349 rotational states of both ortho- and para-water under varying conditions of gas temperature, density, water abundance, and radiation field. It is shown that, under those conditions believed to prevail around late-type stars and within star-forming regions, strong millimeter and submillimeter water maser emission can be generated by collisional excitations by H2. Several maser transitions can have strengths close to that of the 22 GHz line. The water maser line which can be observed from mountaintop facilities and those which will require air- or space-borne platforms are indicated. The exact portion of parameter space in which each maser transition exhibits peak emission is shown. 42 refs.

• OSTI ID: 5758055
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 368; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
AMPLIFIERS
DENSITY
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
ELEMENT ABUNDANCE
EMISSION SPECTRA
ENERGY-LEVEL TRANSITIONS
EQUIPMENT
EXCITATION
HYDROGEN COMPOUNDS
INFRARED RADIATION
INTERSTELLAR SPACE
MASERS
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIATIONS
SPACE
SPECTRA
STAR EVOLUTION
WATER