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Influence of doppler width fluctuations on the shape of spectral lines
NICOLAY SILANTIEV ALEKSEEVICH
EVGUENI LEKHT EVGUENIEVICH
Acceso Abierto
Atribución-NoComercial-SinDerivadas
Masers
Radiative transfer
Stars: atmospheres
Turbulence
We investigate the influence of stochastic Doppler width fluctuations on the shape of spectral lines. The photospheres and atmospheres of stars, and the interstellar medium, possess stochastic behavior especially near nonstationary objects such as active galactic nuclei, quasars, flare stars, and regions of star formation. In reality, we observe the mean values of intensities from these objects. In most situations, the spectral line extinction coefficient has a Gaussian shape with the stochastic Doppler width determined by thermal and small-scale turbulent motions of atoms or molecules. For small-scale turbulent motions (short-correlated turbulence) the propagation of radiation is described by the average extinction factor. This coefficient depends on the level of the Doppler width fluctuations η. We show that these fluctuations change both the value of intensity and the shape of spectral lines. We consider distortions of the spectral line shapes for the absorption and emission lines for various values of the parameter η. For a number of H₂O maser sources we estimate the values of this parameter, the optical depths of the inverted media, and the mean effective Doppler velocities. Maser emission lines with non-Gaussian shape can serve as an additional method for the investigation of the physical parameters in maser “spots.”
The Astrophysical Journal
10-05-2009
Artículo
Inglés
Estudiantes
Investigadores
Público en general
Silant’ev, N. A., et al., (2009). Influence of doppler width fluctuations on the shape of spectral lines, The Astrophysical Journal. Vol.696(2):1972–1980
ASTRONOMÍA Y ASTROFÍSICA
Versión aceptada
acceptedVersion - Versión aceptada
Aparece en las colecciones: Artículos de Astrofísica

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