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Detection of a high frequency break in the X-ray power spectrum of Ark 564

I. E. Papadakis·W. Brinkmann·H. Negoro·M. Gliozzi
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Abstract

We present a power spectrum analysis of the long ASCA observation of Ark 564 in June/July 2001. The observed power spectrum covers a frequency range of ~ 3.5 decades. We detect a high frequency break at ~ 0.002 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. 2001), the observed power spectra of Ark 564 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 (~ 10e{3-4}), 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 Ark 564.

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I. E. Papadakis, W. Brinkmann, H. Negoro, M. Gliozzi. 2001-12-29. Detection of a high frequency break in the X-ray power spectrum of Ark 564. https://doi.org/10.1051/0004-6361%3A20011763

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