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X-ray variability of 104 active galactic nuclei

Published online by Cambridge University Press:  21 February 2013

O. González-Martín  and
S. Vaughan
O. González-Martín
Affiliation:
Instituto de Astrofísica de Canarias (IAC), C/Vía Láctea, s/n, E-38205 La Laguna, Spain Departamento de Astrofísica, Universidad de La Laguna (ULL), E-38205 La Laguna, Spain Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía, s/n 18008 Granada, Spain
S. Vaughan
Affiliation:
Department of Physics and Astronomy, Leicester University, Leicester LE1 7RH, UK email: [email protected]
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Abstract

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We have performed a uniform analysis of the power spectrum densities (PSDs) of 104 nearby (z<0.4) active galactic nuclei (AGN) using 209 XMM-Newton/pn observations, including several AGN classes. These PSDs span ≃ 3 decades in temporal frequencies, ranging from minutes to days. We have fitted each PSD to two models: (1) a single power-law model and (2) a bending power-law model. A fraction of 72% show significant variability. The PSD of the majority of the variable AGN was well described by a simple power-law with a mean index of α = 2.01±0.01. In 15 sources we found that the bending power law model was preferred with a mean slope of α = 3.08±0.04 and a mean bend frequency of 〈νb〉 ≃ 2 × 10−4 Hz. Only KUG 1031+398 (RE J1034+396) shows evidence for quasi-periodic oscillations. The ‘fundamental plane’ relating variability timescale, black hole mass, and luminosity is demonstrated using the new X-ray timing results presented here together with a compilation of the previously detected timescales from the literature.

Keywords

Accretionaccretion disks - Galaxies:active - Galaxies:nuclei - X-ray:galaxies
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 8 , Symposium S290: Feeding Compact Objects: Accretion on All Scales , August 2012 , pp. 37 - 40
Copyright
Copyright © International Astronomical Union 2013

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