Monday, September 11, 2023

Mysterious Black Hole Twins May Fuel The Brightest Galaxies in Space


We propose that AGN flux variability and changes in jet morphology can both be of deterministic nature, i.e., having a geometric/kinetic origin linked to the time-variable Doppler beaming of the jet emission as its direction changes due to precession (and nutation).

We demonstrate this modulating power of precession for OJ 287. For the first time, we show that the spectral state of the spectral energy distribution (SED) can be directly related to the jet's precession phase.

We show that for OJ 287 precession seems to dominate the long-term variability (≳1 yr) of the AGN flux, SED spectral state, and jet morphology, while stochastic processes affect the variability on short timescales (≲0.2 yr).

OJ 287 is an incredibly interesting object. It's a massive quasar that we've observed periodic outbursts in for >100 years, which are attributed to a ~100 million solar mass black hole orbiting a much larger 18 billion solar mass black hole. (For context, the huge M87 black hole was "only" 6 billion solar masses). This paper specifically attributes the emission to the precessing jet caused by the orbiting black holes.


Led by astronomer Silke Britzen of the Max Planck Institute for Radio Astronomy in Germany, an international team studied 12 blazar galaxies, finding an interpretation of circling black holes could be applied to all of them.

This could be a clue as to how supermassive black holes millions to billions of times the mass of the Sun grow to such tremendous size.

We currently lack instrumentation with the resolution to observe the disk architecture that would reveal these binary black holes, but continued monitoring of the precession, as well as long-term observation of other blazars, could continue to yield information about their existence.

Jets blasted out by feeding supermassive black holes at the hearts of active galaxies could brighten and curve due to a "wobble" caused by a second orbiting supermassive black hole, a new study reports.

"We present evidence and discuss the possibility that it is, in fact, the precession of the jet source, either caused by a supermassive binary black hole at the footpoint of the jet or — less likely — by a warped accretion disk around a single black hole, that is responsible for the observed variability," study leader Silke Britzen, a researcher at the Max Planck Institute for Radio Astronomy in Bonn, Germany, said in a statement.

The team can't fully rule out factors in jet physics, such as shock waves or instabilities in the jet, or even magnetic fields, as the driving force behind the curved jets. However, they argue, the jets in question wouldn't be quite as curvy or as bright if it weren't for their wobble.


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