MOMO. VI. Multifrequency Radio Variability of the Blazar OJ 287 from 2015 to 2022, Absence of Predicted 2021 Pecursor-flare Activity, and a New Binary Interpretation of the 2016/2017 Outburst

Creators: Komossa, S.; Kraus, A.; Grupe, D.; Gonzalez, A. G.; Gurwell, M. A.; Gallo, L. C.; Liu, F. K.; Myserlis, I.; Krichbaum, T. P.; Laine, S.; Bach, U.; Gómez, J. L.; Parker, M. L.; Yao, S.; Berton, M.

Abstract

Based on our dedicated Swift monitoring program, MOMO, OJ 287 is one of the best-monitored blazars in the X-ray–UV–optical regime. Here, we report results from our accompanying, dense, multifrequency (1.4–44 GHz) radio monitoring of OJ 287 between 2015 and 2022 covering a broad range of activity states. Fermi γ-ray observations were added. We characterize the radio flux and spectral variability in detail, including discrete correlation function and other variability analyses, and discuss its connection with the multiwavelength emission. Deep fades of the radio and optical–UV fluxes are found to occur every 1–2 yr. Further, it is shown that a precursor flare of thermal bremsstrahlung predicted by one of the binary supermassive black hole (SMBH) models of OJ 287 was absent. We then focus on the nature of the extraordinary, nonthermal, 2016/2017 outburst that we initially discovered with Swift. We interpret it as the latest of the famous optical double-peaked outbursts of OJ 287, favoring binary scenarios that do not require a highly precessing secondary SMBH.

Additional Information

© 2023. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. It is our great pleasure to thank the Swift team for carrying out the observations of OJ 287 that we proposed, and for very useful discussions regarding the observational set-up and related questions throughout the years. We would like to thank Alan Roy for useful comments on the manuscript. This work is partly based on data obtained with the 100 m telescope of the Max-Planck-Institut für Radioastronomie at Effelsberg. The Submillimeter Array near the summit of Maunakea is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. The authors recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This research has made use of the XRT Data Analysis Software (XRTDAS) developed under the responsibility of the ASI Science Data Center (SSDC), Italy. This work has made use of Fermi-LAT data supplied by Kocevski et al. (2021) at https://fermi.gsfc.nasa.gov/ssc/data/access/lat/LightCurveRepository/. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Facilities: Effelsberg 100 m radio telescope - , SMA - , Neil Gehrels Swift observatory (XRT and UVOT) - , Fermi. - Software: HEASoft (https://heasarc.gsfc.nasa.gov/docs/software/heasoft/) with XSPEC (Arnaud 1996), ESO-MIDAS (https://www.eso.org/sci/software/esomidas/), the R programming language (https://www.r-project.org/), SFA (Gallo et al. 2018, https://github.com/Starkiller4011/SFA), and Python (https://www.python.org/).

Attached Files

Published - Komossa_2023_ApJ_944_177.pdf

Files

Komossa_2023_ApJ_944_177.pdf

Files (1.6 MB)

Name	Size	Download all
Komossa_2023_ApJ_944_177.pdf md5:e28d7beb4fc915aefd235d202f36debf	1.6 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes