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MOMO – V. Effelsberg, Swift, and Fermi study of the blazar and supermassive binary black hole candidate OJ 287 in a period of high activity

Komossa, S. and Grupe, D. and Kraus, A. L. and Gonzalez, A. and Gallo, L. C. and Valtonen, M. J. and Laine, S. and Krichbaum, T. P. and Gurwell, M. A. and Gómez, J. L. and Ciprini, S. and Myserlis, I. and Bach, U. (2022) MOMO – V. Effelsberg, Swift, and Fermi study of the blazar and supermassive binary black hole candidate OJ 287 in a period of high activity. Monthly Notices of the Royal Astronomical Society, 513 (3). pp. 3165-3179. ISSN 0035-8711. doi:10.1093/mnras/stac792.

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We report results from our ongoing project MOMO (Multiwavelength Observations and Modelling of OJ 287). In this latest publication of a sequence, we combine our Swift UVOT–XRT and Effelsberg radio data (2.6–44 GHz) between 2019 and 2022.04 with public SMA data and gamma-ray data from the Fermi satellite. The observational epoch covers OJ 287 in a high state of activity from radio to X-rays. The epoch also covers two major events predicted by the binary supermassive black hole (SMBH) model of OJ 287. Spectral and timing analyses clearly establish: a new UV–optical minimum state in 2021 December at an epoch where the secondary SMBH is predicted to cross the disc surrounding the primary SMBH; an overall low level of gamma-ray activity in comparison to pre-2017 epochs; the presence of a remarkable, long-lasting UV–optical flare event of intermediate amplitude in 2020–2021; a high level of activity in the radio band with multiple flares; and particularly a bright, ongoing radio flare peaking in 2021 November that may be associated with a gamma-ray flare, the strongest in 6 yr. Several explanations for the UV–optical minimum state are explored, including the possibility that a secondary SMBH launches a temporary jet, but the observations are best explained by variability associated with the main jet.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper ItemSwift data archive
Grupe, D.0000-0002-9961-3661
Kraus, A. L.0000-0001-9811-568X
Gonzalez, A.0000-0002-0933-8601
Valtonen, M. J.0000-0001-8580-8874
Laine, S.0000-0003-1250-8314
Krichbaum, T. P.0000-0002-4892-9586
Gurwell, M. A.0000-0003-0685-3621
Myserlis, I.0000-0003-3025-9497
Bach, U.0000-0002-7722-8412
Additional Information:© The Author(s) 2022. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. Accepted 2022 March 18. Received 2022 March 1; in original form 2022 January 20. Published: 24 March 2022. It is our pleasure to thank the Swift team for carrying out the observations we proposed and for very useful discussions. We would like to thank Phil Evans for very useful discussions. 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 is partly based on data obtained with the 100-m telescope of the Max-Planck-Institut für Radioastronomie at Effelsberg. The Submillimetre 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 work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester. This work has made use of Fermi-LAT data supplied by Kocevski et al. 2021, 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. Data Availability Statement: Reduced data are available on reasonable request. The raw data of our project are available in the Swift data archive at
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Smithsonian InstitutionUNSPECIFIED
Academia SinicaUNSPECIFIED
Subject Keywords:galaxies: active –galaxies: jets –galaxies: nuclei –quasars: individual (OJ 287) –(galaxies:) quasars: supermassive black holes –X-rays: galaxies
Issue or Number:3
Record Number:CaltechAUTHORS:20220719-515516500
Persistent URL:
Official Citation:S Komossa, D Grupe, A Kraus, A Gonzalez, L C Gallo, M J Valtonen, S Laine, T P Krichbaum, M A Gurwell, J L Gómez, S Ciprini, I Myserlis, U Bach, MOMO – V. Effelsberg, Swift, and Fermi study of the blazar and supermassive binary black hole candidate OJ 287 in a period of high activity, Monthly Notices of the Royal Astronomical Society, Volume 513, Issue 3, July 2022, Pages 3165–3179,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:115685
Deposited By: Tony Diaz
Deposited On:20 Jul 2022 16:05
Last Modified:20 Jul 2022 16:05

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