@article{57d42f1193aa4d73b4560a022823619c,
title = "The universal shape of the X-ray variability power spectrum of AGN up to z ~3",
abstract = "Aims. We study the ensemble X-ray variability properties of active galactic nuclei (AGN) over large ranges of timescale (20 ks ≤ T ≤ 14 yr), redshift (0 ≤ z ≲ 3), luminosity (1040 erg s−1 ≤ LX ≤ 1046 erg s−1), and black hole (BH) mass (106 ≤ M⊙ ≤ 109). Methods. We propose the use of the variance-frequency diagram as a viable alternative to the study of the power spectral density (PSD), which is not yet accessible for distant, faint, and/or sparsely sampled AGN. Results. We show that the data collected from archival observations and previous literature studies are fully consistent with a universal PSD form, which does not show any evidence for systematic evolution of shape or amplitude with redshift or luminosity, even if there may be differences between individual AGN at a given redshift or luminosity. We find new evidence that the PSD bend frequency depends on BH mass and possibly on accretion rate. We finally discuss the implications for current and future AGN population and cosmological studies.",
author = "M. Paolillo and Papadakis, {I. E.} and Brandt, {W. N.} and Bauer, {F. E.} and G. Lanzuisi and V. Allevato and O. Shemmer and Zheng, {X. C.} and {De Cicco}, D. and R. Gilli and B. Luo and M. Thomas and P. Tozzi and F. Vito and Xue, {Y. Q.}",
note = "Funding Information: I.E.P. thanks the University of Naples Federico II for the financial support provided by the International Mobility program. M.P. acknowledges financial support received through the agreement ASI-INAF n.2017-14-H.O. W.N.B. acknowledges support from Chandra X-ray Center grant GO9-20099X and the V.M. Willaman Endowment. F.E.B. acknowledges support from ANID-Chile BASAL AFB-170002 and FB210003, FONDECYT Regular 1200495 and 1190818, and Millennium Science Initiative Program – ICN12_009. Y.Q.X. acknowledges support from NSFC grants (12025303 and 11890693), the K.C. Wong Education Foundation, and the National Key R&D Program of China No. 2022YFF0503401. B.L. acknowledges financial support from the National Natural Science Foundation of China grant 11991053. D.D. acknowledges support from PON R&I 2021, CUP E65F21002880003. This work has made use of lightcurves provided by the University of California, San Diego Center for Astrophysics and Space Sciences, X-ray Group (R.E. Rothschild, A.G. Markowitz, E.S. Rivers, and B.A. McKim), obtained at https://cass.ucsd.edu/~rxteagn/ . Publisher Copyright: {\textcopyright} 2023 EDP Sciences. All rights reserved.",
year = "2023",
month = may,
day = "1",
doi = "10.1051/0004-6361/202245291",
language = "English (US)",
volume = "673",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",
}