EDP Sciences
Free access
Volume 431, Number 3, March I 2005
Page(s) 1167 - 1175
Section Instruments, observational techniques, and data processing
DOI http://dx.doi.org/10.1051/0004-6361:20041601

A&A 431, 1167-1175 (2005)
DOI: 10.1051/0004-6361:20041601

Evolution strategies applied to the problem of line profile decomposition in QSO spectra

R. Quast, R. Baade and D. Reimers

Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
    e-mail: [rquast;rbaade;dreimers]@hs.uni-hamburg.de

(Received 5 July 2004 / Accepted 16 October 2004)

We describe the decomposition of QSO absorption line ensembles by applying an evolutionary forward modelling technique. The modelling is optimized using an evolution strategy (ES) based on a novel concept of completely derandomized self-adaption. The algorithm is described in detail. Its global optimization performance in decomposing a series of simulated test spectra is compared to that of classical deterministic algorithms. Our comparison demonstrates that the ES is a highly competitive algorithm capable of calculating the optimal decomposition without requiring any particular initialization.

Key words: methods: data analysis -- methods: numerical -- galaxies: quasars: absorption lines

© ESO 2005