OJ 287: Supermassive Black Hole Binary Discovery
Unveiling OJ 287’s Plasma Jet: A Ribbon of Extreme Energy
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A New Image Reveals Unprecedented Detail of a Cosmic Phenomenon
Heidelberg,Germany – Astronomers have captured an unprecedentedly detailed image of the plasma jet emanating from the supermassive black hole binary system OJ 287. This groundbreaking observation, made possible by a combination of radio telescopes, reveals a sharply curved, ribbon-like structure and offers new insights into the extreme physics at play near these cosmic behemoths.
OJ 287: A Unique Cosmic Laboratory
OJ 287, located at a redshift of z = 0.306,is a prominent member of the BL Lacertae (BL lac) class of active galactic nuclei. These objects are characterized by their rapid, large-amplitude variability and significant polarization across multiple wavebands. This behavior is attributed to relativistic jets – powerful streams of plasma ejected from the vicinity of a black hole - that are aligned closely with our line of sight.
The galaxy’s unique nature is further underscored by its exceptionally long observational history. Optical observations dating back to the 1880s have provided a light curve spanning nearly 150 years, revealing periodic brightness fluctuations. Most notably, a prominent 60-year cycle and recurrent, doubly peaked high-luminosity flares approximately every 12 years have been observed. These periodic variations are strongly indicative of a binary supermassive black hole system, where a secondary black hole orbits a more massive primary in a precessing, eccentric path.
A Ribbon of Plasma: new Insights from RadioAstron
The new image, a result of observations using the RadioAstron space radio telescope and 27 ground-based observatories, penetrates deep into the galaxy’s centre, showcasing the plasma jet with remarkable clarity. ”we have never before observed a structure in the OJ 287 galaxy at the level of detail seen in the new image,” stated Dr. Efthalia Traianou of Heidelberg University, lead author of the study.”The image reveals the sharply curved, ribbon-like structure of the jet.”
This detailed view provides crucial new data about the composition and behavior of the plasma jet. “Some regions exceed temperatures of 10 trillion Kelvin – evidence of extreme energy and movement being released in close proximity to a black hole,” Dr. Traianou explained.
Shock Waves and the Dance of Black Holes
The astronomers also observed the formation, spread, and collision of a new shock wave along the jet. This phenomenon is linked to an energy release in the trillion-electron volt range, perhaps stemming from an unusual gamma-ray measurement recorded in 2017.
The interferometric imaging technique employed in this study, which leverages the wave nature of light and the overlapping of waves, is basic to achieving such high resolution. The researchers emphasize that the resulting image strongly supports the hypothesis of a binary supermassive black hole residing within OJ 287. Furthermore, it offers vital clues about how the movements of these black holes influence the shape and orientation of the emitted plasma jets.
A Prime Target for Future Research
The unique properties of OJ 287 make it an ideal candidate for continued research into the complex dynamics of merging black holes and the associated gravitational waves. Understanding these extreme cosmic events is crucial for advancing our knowlege of gravity, black hole physics, and the evolution of galaxies.
The findings of this study have been published in the journal Astronomy & Astrophysics.
Image Credit: Efthalia Traianou / Heidelberg University / IWR.
Reference: E. Traianou et al. 2025. Revealing a ribbon-like jet in OJ 287 with RadioAstron. A&A* 700,A16; doi: 10.1051/0004-6361/202554929