Issue |
A&A
Volume 686, June 2024
|
|
---|---|---|
Article Number | A300 | |
Number of page(s) | 7 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361/202449515 | |
Published online | 21 June 2024 |
Unveiling the periodic variability patterns of the X-ray emission from the blazar PG 1553+113
1
INAF – Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monte Porzio Catone, RM, Italy
e-mail: tommaso.aniello@inaf.it
2
“Sapienza” Università di Roma – Dip. di Fisica, P.le A. Moro 5, 00185 Roma, Italy
3
Università degli Studi di Roma “Tor Vergata” – Dip. di Fisica, Via della Ricerca Scientifica 1, 00133 Roma, Italy
4
INFN – Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy
5
University of Maryland – Dept. of Astronomy, College Park, MD 20742, USA
6
NASA – Goddard Space Flight Center, Greenbelt Rd. 8800, Greenbelt, MD 20771, USA
7
ASI – Space Science Data Center, Via del Politecnico snc, 00133 Roma, Italy
8
Scuola Normale Superiore di Pisa, P.zza dei Cavalieri 7, 56126 Pisa, Italy
Received:
6
February
2024
Accepted:
5
April
2024
The search for periodicity in the multiwavelength, highly variable emission of blazars is a key feature to understanding dynamical processes at work in this class of active galactic nuclei. The blazar PG 1553+113 is an attractive target due to the evidence of periodic oscillations observed at different wavelengths, with a solid proof of a 2.2-year modulation detected in the γ-ray, UV, and optical bands. We aim to investigate the variability pattern of the PG 1553+113 X-ray emission using a more than 10-year-long light curve in order to robustly assess the presence or lack of a periodic behavior, evidence of which is only marginal so far. We conducted detailed statistical analyses, studying in particular the variability properties of the X-ray emission of PG 1553+113 by computing the Lomb-Scargle periodograms, which are suited for the analyses of unevenly sampled time series, and adopting epoch-folding techniques. We find a modulation pattern in the X-ray light curve of PG 1553+113 with a period of ∼1.4 years, which is about 35% shorter than the one observed in the γ-ray domain. Our finding is in agreement with the recent spectro-polarimetric analyses and supports the presence of more dynamical phenomena simultaneously at work in the central engine of this quasar.
Key words: black hole physics / galaxies: active / BL Lacertae objects: general / BL Lacertae objects: individual: PG 1553+113 / X-rays: galaxies / X-rays: general
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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