New research, published Wednesday, 24 October, in the journal Monthly Notices of the Royal Astronomical Society, has found evidence for a large number of double supermassive black holes, likely precursors of gigantic black hole merging events. This confirms the current understanding of cosmological evolution - that galaxies and their associated black holes merge over time, forming bigger and bigger galaxies and black holes.

Astronomers from the University of Hertfordshire, together with an international team of scientists, have looked at radio maps of powerful jet sources and found signs that would usually be present when looking at black holes that are closely orbiting each other.

Before black holes merge they form a binary black hole, where the two black holes orbit around each other. Gravitational wave telescopes have been able to evidence the merging of smaller black holes since 2015, by measuring the strong bursts of gravitational waves that are emitted when binary black holes merge, but current technology cannot be used to demonstrate the presence of supermassive binary black holes.

Supermassive black holes emit powerful jets. When supermassive binary black holes orbit it causes the jet emanating from the nucleus of a galaxy to periodically change its direction. Astronomers from the University of Hertfordshire studied the direction that these jets are emitted in, and variances in these directions; they compared the direction of the jets with the one of the radio lobes (that store all the particles that ever went through the jet channels) to demonstrate that this method can be used to indicate the presence of supermassive binary black holes.

Dr. Martin Krause, lead author and senior lecturer in Astronomy at the University of Hertfordshire, said: "We have studied the jets in different conditions for a long time with computer simulations. In this first systematic comparison to high-resolution radio maps of the most powerful radio sources, we were astonished to find signatures that were compatible with jet precession in three quarters of the sources."

The fact that the most powerful jets are associated with binary black holes could have important consequences for the formation of stars in galaxies; stars form from cold gas, jets heat this gas and thus suppress the formation of stars. A jet that always heads in the same direction only heats a limited amount of gas in its vicinity.

However, jets from binary black holes change direction continuously. Therefore, they can heat much more gas, suppressing the formation of stars much more efficiently, and thus contributing towards keeping the number of stars in galaxies within the observed limits.

Research Report: "How Frequent Are Close Supermassive Binary Black Holes in Powerful Jet Sources?," M.G.H. Krause, S.S. Shabala, M.J. Hardcastle et al., 2018 Sep. 21, Monthly Notices of the Royal Astronomical Society

Related Links
University Of Hertfordshire
Understanding Time and Space

Tweet

Thanks for being here; We need your help. The Space Media Network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceMediaNetwork Contributor $5 Billed Once credit card or paypal		SpaceMediaNetwork Monthly Supporter $5 Billed Monthly paypal only

How to weigh a black hole with the Webb Space Telescope
Baltimore MD (SPX) Oct 22, 2018
At first glance, the galaxy NGC 4151 looks like an average spiral. Examine its center more closely, though, and you can spot a bright smudge that stands out from the softer glow around it. That point of light marks the location of a supermassive black hole weighing about 40 million times as much as our Sun. Astronomers will use NASA's James Webb Space Telescope to measure that black hole's mass. The result might seem like a piece of trivia, but its mass determines how a black hole feeds and affect ... read more