Bibcode
DOI
Socas-Navarro, H.; Ruiz-Cobo, B.; Trujilo-Bueno, J.
Bibliographical reference
The Astrophysical Journal, Volume 507, Issue 1, pp. 470-481.
Advertised on:
11
1998
Journal
Citations
54
Refereed citations
44
Description
In this paper we address the problem of the non-LTE (NLTE) inversion of
line profiles by means of a nonlinear least-squares minimization
procedure combined with very efficient multilevel transfer methods. Our
approach is based on the concept of response functions, which measure
the first-order response of the emergent profiles to changes in the
atmospheric conditions. We introduce the fixed departure coefficients
(FDC) approximation in order to compute these response functions in a
fast and straightforward manner. The accuracy of this approximation is
checked comparing FDC response functions with those obtained from full
NLTE computations. An NLTE inversion code based on these response
functions has been developed and extensively tested. Reference synthetic
profiles, similar to those expected from real observations, are given as
input to the inversion algorithm and the recovered models are shown to
be compatible with the reference models within the error bars. Our NLTE
inversion code thus provides a new tool for the investigation of the
chromospheres of the Sun and other stars.