Fast and accurate approximation of the angle-averaged redistribution function for polarized radiation
Additional information
Authors
Paganini A.,
Hashemi B.,
Alsina Ballester E.,
Belluzzi L.
Type
Journal Article
Year
2021
Language
English
Abstract
Context. Modeling spectral line profiles taking frequency redistribution effects into account is a notoriously challenging problem from the computational point of view, especially when polarization phenomena (atomic polarization and polarized radiation) are taken into account. Frequency redistribution effects are conveniently described through the redistribution function formalism, and the angle-averaged approximation is often introduced to simplify the problem. Even in this case, the evaluation of the emission coefficient for polarized radiation remains computationally costly, especially when magnetic fields are present or complex atomic models are considered. textbackslash Aims: We aim to develop an efficient algorithm to numerically evaluate the angle-averaged redistribution function for polarized radiation. textbackslash Methods: The proposed approach is based on a low-rank approximation via trivariate polynomials whose univariate components are represented in the Chebyshev basis. textbackslash Results: The resulting algorithm is significantly faster than standard quadrature-based schemes for any target accuracy in the range [10$^-6$, 10$^-2$].
Journal
Astronomy and Astrophysics
Volume
645
Start page number
A4
Keywords
irsol-refereed-scientific-papers
