Results 1 to 10 of about 440 (199)
Radiative Instabilities in Three-dimensional Astrophysical Masers [PDF]
Astrophysical Journal, 1995 Inherent instabilities in the radiative transfer for astrophysical masers have been recognized and calculated in the linear maser idealization in our previous investigations. The same instabilities are now shown to occur in the more realistic, three-dimensional geometries.
William D Watson
exaly +4 more sources
Astrophysical water masers: Line profiles analysis [PDF]
Astronomy and Astrophysics, 2005 The changes in the spectral line profile of the 22GHz H2O maser are calculated as a function of emerging maser flux. We address not only the narrowing and re-broadening of the maser lines, but also the deviations of Gaussian symmetry as a result of the various hyperfine components of the 22 GHz maser line.
H J Van Langevelde
exaly +4 more sources
Images of Astrophysical Masers and their Variability in a Turbulent Medium: The 25 GHz Methanol Masers [PDF]
Astrophysical Journal, 2003 We examine the influence of chance coherences in turbulent velocities for the creation of the images of astrophysical masers. Images are computed that represent the numerous masing features that are commonly observed in an extended masing region. Changes as a function of Doppler velocity can be seen in the appearance of these images. Variability in the
A M Sobolev, W D Watson
exaly +3 more sources
Astrophysical Maser Radiation from a Turbulent Medium: Application to 25 GHz Methanol Masers [PDF]
Astrophysical Journal, 1998 Spectral and spatial distributions are calculated for astrophysical maser radiation that emerges from a turbulent medium. Turbulent-velocity fields are created by sampling from Kolmogorov-like distributions. The maps of maser emission created in a turbulent medium appear as if the emission results from a collection of isolated clumps moving with ...
A M Sobolev, B K Wallin, W D Watson
exaly +3 more sources
Interacting masers and the extreme brightness of astrophysical water masers
Astrophysical Journal, 1989 Extreme surface brightnesses have long been reported for water masers which are well beyond what is found in self-consistent, theoretical investigations of these masers. The transport of maser radiation is calculated when two masers, having the properties inferred for the numerous weaker masers and separated by distances characteristic of the molecular
Shuji Deguchi, William D Watson
exaly +2 more sources
Saturation and beaming in astrophysical masers. III - Asymmetrically pumped masers
Astrophysical Journal, 1986 There is reason to believe that the physical conditions in many astrophysical masers are far from homogeneous. In particular, if the maser pump involves the absorption of infrared photons, the pump rate may vary rapidly (perhaps exponentially) across the cloud.
C Alcock, R R Ross
exaly +2 more sources
Gaussian Spectral Line Profiles of Astrophysical Masers
Astrophysical Journal, 2002 4 pages with 3 figures embedded in paper; uses AASTEX with emulateapj5.sty; accepted for publication in ApJ (Letters)
W D Watson, A P Sarma
exaly +3 more sources
Spectral line profiles and luminosities of astrophysical water masers
Astrophysical Journal, 1991 The spectral line narrowing and rebroadening that occurs for astrophysical masers as a function of the emergent radiative flux is calculated for the prominent, 22 GHz masing transition of water. The increased line breadths due to hyperfine structure lead to reliable, essentially model-independent upper limits to the emergent flux that tend to be lower ...
Gerald E Nedoluha, William D Watson
exaly +2 more sources
The Astrophysical Journal, 2023 Because of detailed monitoring of the 22.2 GHz water maser, carried out from 2021 October to 2023 May, a very powerful flare phenomenon was detected in the galactic object W51 near the radial velocity of 60 km s ^−1 with the amplitude of 140 kJy.
A. E. Volvach +2 more
doaj +1 more source
An Updated Reference Frame for the Galactic Inner Parsec
The Astrophysical Journal, 2023 Infrared observations of stellar orbits about Sgr A* probe the mass distribution in the inner parsec of the Galaxy and provide definitive evidence for the existence of a massive black hole.
Jeremy Darling +5 more
doaj +1 more source