Radiative transfer in moving media

Korčáková, Daniela; Kubát, Jiřı́

doi:10.1051/0004-6361:20041992

Cited by 13 publications

(14 citation statements)

References 21 publications

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“…The hydrostatic structure, together with the opacity and source function, is calculated with the NLTE accretion disc code AcDc (Nagel et al 2004). The output from this code serves as input for the radiative transfer code (Korčáková & Kubát 2005), which is used for the formal solution of the radiative transfer equation in the comoving frame.…”

Section: Model Descriptionmentioning

confidence: 99%

“…Instead, the final formal solution of the radiative transfer equation is calculated using the 2.5D radiative transfer code Korčáková & Kubát (2005). The main assumption of this model is axial symmetry.…”

Section: 5d Radiative Transfer Modelmentioning

confidence: 99%

“…The optical properties of the medium are interpolated from the accurate disc structure solutions along the vertical coordinate at different radii using the NLTE approach (Nagel et al 2004). We use the accurate ray-tracing method for the radiation transfer equation in moving media (Korčáková & Kubát 2005).…”

Section: Introductionmentioning

confidence: 99%

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Influence of the velocity gradient on the line formation in discs of cataclysmic variables

Korčáková

Nagel²,

Werner³

et al. 2011

A&A

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Context. The velocity field gradient in the radiative transfer in disc models of cataclysmic variables (CVs) is usually neglected; however, the geometry of the system and the value of Keplerian velocity suggest that it can be important for high inclination angles. Aims. We investigate the influence of the Keplerian velocity gradient on the line formation in CV discs. Methods. The vertical structure of the disc was determined using the NLTE accretion disc code AcDc, where the hydrostatic equation, the energy balance equation, the radiative transfer equation, the rate equations, and the equations of charge and particle conservation are consistently solved using the accelerated lambda iteration. NLTE opacities and emissivities are interpolated onto a 2D grid, where the radiative transfer equation was then solved with the velocity field taken into account. Results. We show line-profile changes and limb-darkening dependences for the Hα and Hγ lines in a model of SS Cyg, along with the HeI 4923 Å line of a model representing a typical AM CVn system. Both systems are considered in the quiescent phase. Conclusions. The line-profile changes due to the velocity gradient in the disc are small enough for most CV discs to allow the classical approach, where the radiative transfer is solved through the static disc and the velocity field is only taken into account in the final flux integration. However, the exact solution must be performed for CVs, where the disc rim plays an important role (inclination angles almost 90 • ). Extremely cool and relatively transparent discs under high inclinations should also be investigated with detailed radiative transfer models.

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Section: Model Descriptionmentioning

confidence: 99%

Section: 5d Radiative Transfer Modelmentioning

confidence: 99%

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Influence of the velocity gradient on the line formation in discs of cataclysmic variables

Korčáková

Nagel²,

Werner³

et al. 2011

A&A

Self Cite

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“…The disc is divided into a set of concentric rings, where the radiative transfer equation (RTE), hydrostatic equilibrium and energy balance equations, and non-LTE rate equations are consistently solved using the Accelerated Lambda Iteration (ALI, Werner & Husfeld 1985). The resulting opacities and source functions are interpolated onto a 2D grid, where the RTE is solved with the inclusion of the velocity field (Korčáková & Kubát 2005). …”

Section: Modelmentioning

confidence: 99%

Influence of Rotation Velocity Gradient on Line Profiles of Accretion Discs of CVs

et al. 2011

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Abstract.We show the influence of the Keplerian velocity shear on the line profiles of cataclysmic variable discs. The complete disc structure is taken into account. The radial disc structure follows the alpha disc approximation. Based on this assumption, the vertical structure is computed using the detailed non-LTE code AcDc. The obtained opacities and source functions are interpolated in the 2D grid, where the radiative transfer is calculated with the inclusion of the velocity field gradient.

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“…We anticipate that such numerical techniques and benchmark results will be of interest for the new radiative transfer codes currently in use or under development, not only for applications in solar physics but also for interstellar clouds (see e.g., Juvela & Padoan 2005), circumstellar environments with winds (see e.g., Georgiev et al 2006) or accretion disks (see e.g., Korčáková & Kubát 2005) modelling for instance.…”

Section: Points Numbermentioning

confidence: 99%

Fast 2D non–LTE radiative modelling of prominences

Léger

Chevallier

Paletou

2007

A&A

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Context. New high-resolution spectropolarimetric observations of solar prominences require improved radiative modelling capabilities in order to take into account both multi-dimensional -at least 2D -geometry and complex atomic models. Aims. This makes necessary the use of very fast numerical schemes for the resolution of 2D non-LTE radiative transfer problems considering freestanding and illuminated slabs. Methods. The implementation of Gauss-Seidel and successive over-relaxation iterative schemes in 2D, together with a multi-grid algorithm, is thoroughly described in the frame of the short characteristics method for the computation of the formal solution of the radiative transfer equation in cartesian geometry. Results. We propose a new test for multidimensional radiative transfer codes and we also provide original benchmark results for simple 2D multilevel atom cases which should be helpful for the further development of such radiative transfer codes, in general.

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Radiative transfer in moving media

Cited by 13 publications

References 21 publications

Influence of the velocity gradient on the line formation in discs of cataclysmic variables

Influence of the velocity gradient on the line formation in discs of cataclysmic variables

Influence of Rotation Velocity Gradient on Line Profiles of Accretion Discs of CVs

Fast 2D non–LTE radiative modelling of prominences

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