The usefulness of analytic response functions*
Instituto de Astrofísica de Andalucía, Consejo Superior de Investigaciones Científicas, Apdo. de Correos 3004, 18080 Granada, Spain e-mail: firstname.lastname@example.org;email@example.com
Accepted: 8 October 2006
Aims.We introduce analytical response functions and their main properties as an important diagnostic tool that help understand Stokes profile formation physics and the meaning of well-known behaviors of standard inversion codes of the radiative transfer equation often used to measure solar magnetic fields.
Methods.A Milne-Eddington model atmosphere is used as an example where response functions are analytical. A sample spectral line has been chosen to show the main qualitative properties.
Results.We show that analytic response functions readily provide explanations for various well-known behaviors of spectral lines, such as the sensitivity of visible lines to weak magnetic fields or the trade-offs often detected in inversion codes between the Milne-Eddington thermodynamic parameters. We also show that response functions are helpful in selecting sample wavelengths optimized for specific parameter diagnostics.
Key words: radiative transfer / magnetic fields / line: formation / polarization / Sun: photosphere / Sun: magnetic fields
© ESO, 2007