18682
2001
2001
eng
article
1
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Nonlinear Time series analysis of the X-ray flux of compact objects
We analyse the X-ray light curves of compact objects using linear and nonlinear time series analysis methods. A Power Density Spectrum (PDS) describes the overall second order properties of the observed data well. To look beyond we propose the nonlinear Q-statistic to detect an asymmetry of the time series. This allows us to find relevant time scales. This method even grants a subclassification of the known states of X-ray sources.
0004-640x
allegro:1991-2014
10095412
Astrophysics and space science. - ISSN: 0004-640x. - (Supplement 1). - 276 (2001), S. 187 - 188
Marco Thiel
Maria Carmen Romano
Udo Schwarz
Jürgen Kurths
Günther Hasinger
Tomaso Belloni
Interdisziplinäres Zentrum für Dynamik komplexer Systeme
19906
2000
2000
eng
article
1
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Linear and Nonlinear Time Series Analysis of the Black Hole Candidate Cygnus X-1
We analyze the variability in the x-ray lightcurves of the black hole candidate Cygnus X-1 by linear and nonlinear time series analysis methods. While a linear model describes the overall second order properties of the observed data well, surrogate data analysis reveals a significant deviation from linearity. We discuss the relation between shot noise models usually applied to analyze these data and linear stochastic autoregressive models. We debate statistical and interpretational issues of surrogate data testing for the present context. Finally, we suggest a combination of tools from linear and nonlinear time series analysis methods as a procedure to test the predictions of astrophysical models on observed data.
http://pre.aps.org/
allegro:1991-2014
10093230
Physical review / E. - 61 (2000), 2, S. 1342 - 1352
Jens Timmer
Udo Schwarz
Henning U. Voss
Ingo Wardinski
Tomaso Belloni
Günther Hasinger
Michael VanDerKlis
Jürgen Kurths
Interdisziplinäres Zentrum für Dynamik komplexer Systeme
Interdisziplinäres Zentrum für Nichtlineare Dynamik