2013/04/25 by T. Taro Shimizu, Richard F. Mushotzky
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysical Phenomena and Observations #Earth Systems and Cosmic Evolution #Galaxies: Formation, Evolution, Phenomena #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.1088/0004-637x/770/1/60
published as Shimizu & Mushotzky 2013 ApJ 770, 60 · 24 pages, 18 figures, 7 tables, accepted for publication in ApJ
arxiv created 2013/04/25 · openalex publication_date 2013/05/24 · arxiv updated 2013/05/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We present results of our power spectral density (PSD) analysis of 30 active galactic nuclei (AGNs) using the 58 month light curves from Swift's Burst Alert Telescope (BAT) in the 14–150 keV band. PSDs were fit using a Monte Carlo based algorithm to take into account windowing effects and measurement error. All but one source were found to be fit very well using an unbroken power law with a slope of ∼ − 1, consistent at low frequencies with previous studies in the 2–10 keV band, with no evidence of a break in the PSD. For five of the highest signal-to-noise ratio sources, we tested the energy dependence of the PSD and found no significant difference in the PSD at different energies. Unlike previous studies of X-ray variability in AGNs, we do not find any significant correlations between the hard X-ray variability and different properties of the AGN including luminosity and black hole mass. The lack of break frequencies and correlations seem to indicate that AGNs are similar to the high state of Galactic black holes.