Volume 382, Number 1, JanuaryIV 2002
|Page(s)||L1 - L4|
|Published online||15 January 2002|
Letter to the Editor
Detection of a high frequency break in the X-ray power spectrum of Ark 564
IESL, Foundation for Research and Technology-Hellas, PO Box 1527, 711 10 Heraklion, Crete, Greece
2 Physics Department, University of Crete, PO Box 2208, 710 03 Heraklion, Greece
3 Max–Planck–Institut für extraterrestrische Physik, Giessenbachstrasse, 85740 Garching, Germany
4 Cosmic Radiation Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-01, Japan
Corresponding author: I. E. Papadakis, email@example.com
Accepted: 10 December 2001
We present a power spectrum analysis of the long ASCA observation of in June/July 2001. The observed power spectrum covers a frequency range of ~3.5 decades. We detect a high frequency break at ~ Hz. The power spectrum has an rms of ~30% and a slope of ~-1 and ~-2 below and above the break frequency. When combined with the results from a long RXTE observation (Pounds et al. [CITE]), the observed power spectra of and Cyg X-1 (in the low/hard state) are almost identical, showing a similar shape and rms amplitude. However, the ratio of the high frequency breaks is very small (~103-4), implying that these characteristic frequencies are not indicative of the black hole mass. This result supports the idea of a small black hole mass/high accretion rate in .
Key words: galaxies: active / galaxies: Seyfert / galaxies: individual: Ark 564 / X-rays: galaxies
© ESO, 2002
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