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Main Authors: Prokhorenko, S. A., Sazonov, S. Yu., Gilfanov, M. R., Balashev, S. A., Bikmaev, I. F., Ivanchik, A. V., Medvedev, P. S., Starobinsky, A. A., Sunyaev, R. A
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2401.12860
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author Prokhorenko, S. A.
Sazonov, S. Yu.
Gilfanov, M. R.
Balashev, S. A.
Bikmaev, I. F.
Ivanchik, A. V.
Medvedev, P. S.
Starobinsky, A. A.
Sunyaev, R. A
author_facet Prokhorenko, S. A.
Sazonov, S. Yu.
Gilfanov, M. R.
Balashev, S. A.
Bikmaev, I. F.
Ivanchik, A. V.
Medvedev, P. S.
Starobinsky, A. A.
Sunyaev, R. A
contents We examine the long-term (rest-frame time scales from a few months to $\sim 20$ years) X-ray variability of a sample of 2344 X-ray bright quasars from the SDSS DR14Q Catalogue, based on the data of the SRG/eROSITA All-Sky Survey complemented for $\sim 7$% of the sample by archival data from the XMM-Newton Serendipitous Source Catalogue. We characterise variability by a structure function, $SF^2(Δt)$. We confirm the previously known anti-correlation of the X-ray variability amplitude with luminosity. We also study the dependence of X-ray variability on black hole mass, $M_{\rm BH}$, and on an X-ray based proxy of the Eddington ratio, $λ_{\rm X}$. Less massive black holes prove to be more variable for given Eddington ratio and time scale. X-ray variability also grows with decreasing Eddington ratio and becomes particularly strong at $λ_{\rm X}$ of less than a few per cent. We confirm that the X-ray variability amplitude increases with increasing time scale. The $SF^2(Δt)$ dependence can be satisfactorily described by a power law, with the slope ranging from $\sim 0$ to $\sim 0.4$ for different ($M_{\rm BH}$, $λ_{\rm X}$) subsamples (except for the subsample with the lowest black hole mass and lowest Eddington ratio, where it is equal to $1.1\pm 0.4$)
format Preprint
id arxiv_https___arxiv_org_abs_2401_12860
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle X-Ray Variability of SDSS Quasars Based on the SRG/eROSITA All-Sky Survey
Prokhorenko, S. A.
Sazonov, S. Yu.
Gilfanov, M. R.
Balashev, S. A.
Bikmaev, I. F.
Ivanchik, A. V.
Medvedev, P. S.
Starobinsky, A. A.
Sunyaev, R. A
High Energy Astrophysical Phenomena
We examine the long-term (rest-frame time scales from a few months to $\sim 20$ years) X-ray variability of a sample of 2344 X-ray bright quasars from the SDSS DR14Q Catalogue, based on the data of the SRG/eROSITA All-Sky Survey complemented for $\sim 7$% of the sample by archival data from the XMM-Newton Serendipitous Source Catalogue. We characterise variability by a structure function, $SF^2(Δt)$. We confirm the previously known anti-correlation of the X-ray variability amplitude with luminosity. We also study the dependence of X-ray variability on black hole mass, $M_{\rm BH}$, and on an X-ray based proxy of the Eddington ratio, $λ_{\rm X}$. Less massive black holes prove to be more variable for given Eddington ratio and time scale. X-ray variability also grows with decreasing Eddington ratio and becomes particularly strong at $λ_{\rm X}$ of less than a few per cent. We confirm that the X-ray variability amplitude increases with increasing time scale. The $SF^2(Δt)$ dependence can be satisfactorily described by a power law, with the slope ranging from $\sim 0$ to $\sim 0.4$ for different ($M_{\rm BH}$, $λ_{\rm X}$) subsamples (except for the subsample with the lowest black hole mass and lowest Eddington ratio, where it is equal to $1.1\pm 0.4$)
title X-Ray Variability of SDSS Quasars Based on the SRG/eROSITA All-Sky Survey
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2401.12860