Multiwavelength astrophysics of the blazar OJ 287 and the project MOMO

TL;DR

This paper presents the MOMO project, a comprehensive multiwavelength monitoring campaign of the blazar OJ 287, aiming to understand its disk-jet physics and test the binary black hole model through extensive observations from radio to high-energy wavelengths.

Contribution

It provides the densest, longest multiyear multiwavelength dataset of OJ 287, including simultaneous observations with EHT, and analyzes flux and spectral evolution to test binary black hole predictions.

Findings

No evidence of precursor flares related to SMBH disk impact.

Observed a bright radio flare and spectral evolution from 2021 to 2022.

Discussions on extreme outburst and minima states in the blazar.

Abstract

We are carrying out the densest and longest multiyear, multiwavelength monitoring project of OJ 287 ever done. The project MOMO (Multiwavelength Observations and Modelling of OJ 287) covers wavelengths from the radio to the high-energy regime. A few selected observations are simultaneous with those of the Event Horizon Telescope (EHT). MOMO aims at understanding disk-jet physics and at testing predictions of the binary black hole scenario of OJ 287. Here, we present a discussion of extreme outburst and minima states in context, and then focus on the recent flux and spectral evolution between 2021 and May 2022, including an ongoing bright radio flare. Further, we show that there is no evidence for precursor flare activity in our optical-UV-X-ray light curves that would be associated with any secondary supermassive black hole (SMBH) disk impact and that was predicted to start as thermal flare on 2021 December 23.