The goodness of simultaneous fits in ISIS

Journal article
(Original article)

Publication Details

Author(s): Kühnel M, Falkner S, Großberger C, Ballhausen R, Dauser T, Schwarm FW, Kreykenbohm I, Nowak MA, Pottschmidt K, Ferrigno C, Rothschild RE, Martínez-Núñez S, Torrejón JM, Fürst F, Klochkov D, Staubert R, Kretschmar P, Wilms J
Journal: Acta Polytechnica
Publisher: Czech Technical University
Publication year: 2016
Volume: 56
Journal issue: 1
Pages range: 41-46
ISSN: 1210-2709
eISSN: 1805-2363


In a previous work, we introduced a tool for analyzing multiple datasets simultaneously, which has been implemented into ISIS. This tool was used to fit many spectra of X-ray binaries. However, the large number of degrees of freedom and individual datasets raise an issue about a good measure for a simultaneous fit quality. We present three ways to check the goodness of these fits: we investigate the goodness of each fit in all datasets, we define a combined goodness exploiting the logical structure of a simultaneous fit, and we stack the fit residuals of all datasets to detect weak features. These tools are applied to all RXTE-spectra from GRO 1008−57, revealing calibration features that are not detected significantly in any single spectrum. Stacking the residuals from the best-fit model for the Vela X-1 and XTE J1859+083 data evidences fluorescent emission lines that would have gone undetected otherwise.

FAU Authors / FAU Editors

Ballhausen, Ralf
Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut
Dauser, Thomas Dr.
Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut
Falkner, Sebastian Dr.
Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut
Großberger, Christoph
Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut
Kreykenbohm, Ingo Dr.
Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut
Schwarm, Fritz-Walter
Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut
Wilms, Jörn Prof. Dr.
Professur für Astronomie und Astrophysik

External institutions with authors

California Institute of Technology (Caltech)
Eberhard Karls Universität Tübingen
European Space Astronomy Centre (ESAC)
Massachusetts Institute of Technology (MIT)
Universitat d'Alacant (UA) / University of Alicante
University of California, San Diego
University of Geneva / Université de Genève (UNIGE)
University of Maryland, Baltimore County

How to cite

Kühnel, M., Falkner, S., Großberger, C., Ballhausen, R., Dauser, T., Schwarm, F.-W.,... Wilms, J. (2016). The goodness of simultaneous fits in ISIS. Acta Polytechnica, 56(1), 41-46.

Kühnel, Matthias, et al. "The goodness of simultaneous fits in ISIS." Acta Polytechnica 56.1 (2016): 41-46.


Last updated on 2018-20-11 at 13:50