Astronomie - The Rosetta stone of active galactic nuclei deciphered A radio jet of a supermassive black hole has been investigated in so far unprecedented detail


A galaxy with at least one active supermassive black hole – named OJ 287 – has caused many irritations and questions in the past. The emitted radiation of this object spans a wide range – from the radio up to the highest energies in the TeV regime. The potential periodicity in the variable optical emission made this galaxy a candidate for hosting a supermassive binary black hole in its centre. The object was thus labeled a Rosetta stone of active galactic nuclei expressing the hope that this object could be a prototypical object and once deciphered, could explain fundamental properties of active black holes in general. Now an international team of astronomers led by Max Planck researchers has discovered that the active galactic nucleus of OJ 287 generates a smoothly precessing jet on a timescale of about 22 years. The precession of the jet observed could also explain the variability in the radiation of the galaxy. This detection solves many riddles at once and provides a key to understanding variability in active galactic nuclei.

The findings are published in the journal Monthly Notices of the Royal Astronomical Society (2018 June 21).


Artist’s impression of the central region of the active galaxy OJ 287 with a preceding jet. The precession could either be caused by a binary black hole (Inset A) or by a mis-aligned accretion disk (Inset B).

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