Possible Quasi-periodic Oscillation in the Distant γ-Ray Blazar PKS 0454–234
Abdou, Y., Hashad, M., Boundok, I., El-Zant, A. (2023). Possible Quasi-periodic Oscillation in the Distant γ-Ray Blazar PKS 0454–234. EKB Journal Management System, 56(3), 155-165. doi: 10.21608/ajnsa.2022.158331.1629
Yasser Abdou; Mohamed Hashad; Ibrahim Boundok; Amr El-Zant. "Possible Quasi-periodic Oscillation in the Distant γ-Ray Blazar PKS 0454–234". EKB Journal Management System, 56, 3, 2023, 155-165. doi: 10.21608/ajnsa.2022.158331.1629
Abdou, Y., Hashad, M., Boundok, I., El-Zant, A. (2023). 'Possible Quasi-periodic Oscillation in the Distant γ-Ray Blazar PKS 0454–234', EKB Journal Management System, 56(3), pp. 155-165. doi: 10.21608/ajnsa.2022.158331.1629
Abdou, Y., Hashad, M., Boundok, I., El-Zant, A. Possible Quasi-periodic Oscillation in the Distant γ-Ray Blazar PKS 0454–234. EKB Journal Management System, 2023; 56(3): 155-165. doi: 10.21608/ajnsa.2022.158331.1629

Possible Quasi-periodic Oscillation in the Distant γ-Ray Blazar PKS 0454–234

Arab Journal of Nuclear Sciences and Applications
Volume 56, Issue 3, April 2023, Page 155-165  XML PDF (1.69 MB)
Document Type: Original Article
DOI: 10.21608/ajnsa.2022.158331.1629
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Authors
Yasser Abdou1; Mohamed Hashad email 2; Ibrahim Boundok3; Amr El-Zant4
1Physics Department, Faculty of Science, Tanta University, Tanta 31527, Egypt
2Basic Science Department, Modern Academy for Engineering and Technology, Maadi 11585, Cairo, Egypt.
3Physics Department, Faculty of Science, Tanta University, Tanta 31527, Tanta, Egypt.
4Centre for Theoretical Physics, The British University in Egypt, Sherouk City 11837, Cairo, Egypt.
Abstract
An important observational feature of Fermi-LAT blazars is their variability, which remarkably occasionally shows quasi-periodic oscillations (QPOs); a characteristic that could convey information regarding the emission mechanism from their central engines, as well as the possibility of observing merging systems. This work searches for 0.1–100 GeV γ-ray periodic modulations in the distant (redshift=1.003) flat-spectrum radio quasar PKS 0454–234, using the Fermi-LAT pass 8 data for time span of about 14 yr. The search for such signals in the γ-ray light curves was carried out using four methods: the Generalized Lomb-Scargle periodogram (GLSP), the weighted wavelet z-transform (WWZ), the REDFIT algorithm, as well as the auto-correlation function. Two possible QPO signals were found with periods of 3.51±0.33 yr and 6.10±0.82 yr, at the significance levels of ~4σ and ~3σ, respectively. Even though the latter periodicity is less significant than the former, it in fact gives a better fit to the fluxes. Considering a super binary black hole system (SBBHS) model, the parameters of the binary were estimated (for the period of 6 yr) as follows: a binary separation of R∼0.005 pc, with total mass M∼4.69×10^8 M⊙, and decay time of the gravitational wave emission T(GW)∼9.56×10^4 yr.
Keywords
Active galactic nuclei; Quasi-periodicity; Non-thermal radiation mechanisms; Gamma-rays
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