Abstract

Since 2016 October, the active galaxy PKS 2247−131 has undergone a γ-ray outburst, which we studied using data obtained with the Fermi Gamma-ray Space Telescope. The emission arises from a relativistic jet in PKS 2247−131, as an optical spectrum only shows a few weak absorption lines, typical of the BL Lacertae sub-class of the blazar class of active galactic nuclei. Here we report a ≃34.5 day quasi-periodic oscillation (QPO) in the emission after the initial flux peak of the outburst. Compared to one-year time-scale QPOs, previously identified in blazars in Fermi energies, PKS 2247−131 exhibits the first clear case of a relatively short, month-like oscillation. We show that this QPO can be explained in terms of a helical structure in the jet, where the viewing angle to the dominant emission region in the jet undergoes periodic changes. The time scale of the QPO suggests the presence of binary supermassive black holes in PKS 2247−131.

Details

Title
A 34.5 day quasi-periodic oscillation in γ-ray emission from the blazar PKS 2247–131
Author
Zhou, Jianeng 1 ; Wang, Zhongxiang 1 ; Chen, Liang 2 ; Wiita, Paul J 3 ; Jithesh Vadakkumthani 4   VIAFID ORCID Logo  ; Morrell, Nidia 5 ; Zhang, Pengfei 6 ; Zhang, Jujia 7 

1  Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai, China 
2  Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China 
3  The College of New Jersey, Ewing, NJ, USA 
4  Inter-University Centre for Astronomy and Astrophysics, Pune, India 
5  Las Campanas Observatory, Carnegie Observatories, La Serena, Chile 
6  Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, China 
7  Yunnan Observatories, Chinese Academy of Sciences, Kunming, China; Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming, China; Center for Astronomical Mega-Science, Chinese Academy of Sciences, Beijing, China 
Pages
1-6
Publication year
2018
Publication date
Nov 2018
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1038/s41467-018-07103-2
ProQuest document ID
2128535313
Copyright
© 2018. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.