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Astron. Astrophys. 354, 847-852 (2000)

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Extraction of a deterministic component from ROSAT X-ray data using a wavelet transform and the principal component analysis

II. The data analysis

L. Liszka 1, A.G. Pacholczyk 2 and W.R. Stoeger S.J. 3

1 Swedish Institute of Space Physics, Umeå Division, Sörfors 634, 905 88 Umeå, Sweden
2 Steward Observatory, The University of Arizona, Tucson, AZ 85721, USA
3 Vatican Observatory Research Group, Steward Observatory, The University of Arizona, Tucson, AZ 85721, USA

Received 27 September 1999 / Accepted 9 December 1999


A deterministic component in the X-ray photon series from Seyfert 1 galaxies and quasars, observed by ROSAT, is studied with the wavelet spectra method. A semi-regular deterministic modulation of the photon series is stronger and occurs more frequently in Seyfert 1 nuclei than in quasars indicating that by studying statistical properties of an X-ray photon train it is possible to identify unambiguously the character of its source. An interpretation of these differences is suggested within a scenario provided by a black hole nuclear cluster paradigm.

Key words: methods: data analysis – methods: statistical – galaxies: quasars: individual: 3C 273 – galaxies: individual: NGC 5548 – galaxies: Seyfert – X-rays: galaxies

Send offprint requests to: L. Liszka (ludwik@irf.se)

© European Southern Observatory (ESO) 2000

Online publication: February 25, 2000