MOMO – V. Effelsberg, Swift, and Fermi study of the blazar and supermassive binary black hole candidate OJ 287 in a period of high activity. Issue 3 (24th March 2022)

• Record Type: Journal Article
• Authors: Komossa, S; Grupe, D; Kraus, A; Gonzalez, A; Gallo, L C; Valtonen, M J; Laine, S; Krichbaum, T P; Gurwell, M A; Gómez, J L; Ciprini, S; Myserlis, I; Bach, U
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 513:Issue 3(2022)
• Page Start: 3165
• Page End: 3179
• Publication Date: 2022-03-24
• Subjects: galaxies: active -- galaxies: jets -- galaxies: nuclei -- quasars: individual (OJ 287) -- (galaxies:) quasars: supermassive black holes -- X-rays: galaxies; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac792
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: 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.