When radio galaxies collide, supermassive black holes form tightly bound pairs

Discovery of the closest binary supermassive black hole system in the galaxy NGC 7674
The two compact radio sources separated by less than a light year at the center of the galaxyNGC7674. The two sources correspond to the location of the two active supermassive blackholes which form a binary and orbit around each other. Credit: TIFR-NCRA and RIT, USA

A study using multiple radio telescopes confirms that supermassive black holes found in the centers of galaxies can form gravitationally bound pairs when galaxies merge.

The paper published in the Sept. 18 issue of Nature Astronomy sheds light on a class of black holes having a mass upwards of one million times the mass of the sun. Supermassive black holes are expected to form tightly bound pairs following the merger of two galaxies.

"The dual black hole we found has the smallest separation of any so far detected through direct imaging," said David Merritt, professor of physics at Rochester Institute of Technology, a co-author on the paper.

The supermassive black holes are located in the spiral galaxy NGC 7674, approximately 400 million light years from earth, and are separated by a distance less than one light year. The study was led by Preeti Kharb, from the National Center for Radio Astrophysics at Pune University in India and co-authored by Dharam Vir Lal, also at Pune University and Merritt at RIT.

"The combined mass of the two black holes is roughly 40 million times the mass of the Sun, and the orbital period of the binary is about 100,000 years," Merritt said.

A class of smaller black holes form when massive stars explode as supernovae. A collision of stellar mass black holes led to the landmark discovery of in 2015 using the Laser Interferometer Gravitational-wave Observatory. The black holes were approximately 29 and 36 times the mass of the sun and collided 1.3 billion light years away

"A supermassive binary generates gravitational waves with much lower frequency than the characteristic frequency of stellar- binaries and its signal is undetectable by LIGO," Merritt said.

To simulate a highly sensitive detector, the researchers used a method to make radio telescopes around the world work together as a single large telescope and achieve a resolution roughly 10 million times the angular resolution of the human eye.

"Using very long baseline interferometry techniques, two compact sources of radio emission were detected at the center of NGC 7674; the two radio sources have properties that are known to be associated with massive black holes that are accreting gas, implying the presence of two ," Merritt said.

The galaxy hosting the binary loudly emits radio waves. The detection confirms a theory predicting the presence of a compact binary in a radio bearing a "Z" shape.

"This morphology is thought to result from the combined effects of the galaxy merger followed by the formation of the massive binary," Merritt said.


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More information: A candidate sub-parsec binary black hole in the Seyfert galaxy NGC 7674, Nature Astronomy (2017). DOI: 10.1038/s41550-017-0256-4
Journal information: Nature Astronomy

Citation: When radio galaxies collide, supermassive black holes form tightly bound pairs (2017, September 18) retrieved 22 August 2019 from https://phys.org/news/2017-09-radio-galaxies-collide-supermassive-black.html
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Sep 18, 2017
Supermassive black holes are expected to form tightly bound pairs following the merger of two galaxies.

A simple assumption from the simple minds of merger maniacs.

"The dual black hole we found has the smallest separation of any so far detected through direct imaging,"

More likely, one core is the daughter of the other core, having birthed therefrom and grown to supermassive status all on it's own through unknown (SubQuantum Kinectic) internal mechanisms.

Sep 19, 2017
It is quite probable, but it is impossible for any interferometer based GW receiver to sense such a wave, even, if the interferometer is thousands of miles long. Primarily, because, gravity still travels at infinite speed as proposed by Newton; Einstein, indeed, could not change the speed. Let me add, 6 years earlier, minuscule gravitational waves of a wide frequency range (nearly zero to around 3 KHz) were first produced and detected in my lab late in 2010 and were reported in a US patent application which now is a US patent 8521029. You can find the patent detail on the USPTO site as well as on https://www.googl...S8521029 . You can check out gravitational waves and my work on Wikipedia. Let me also add, even if I am letting out a little secret, it is impossible to register any black hole mergers, because of the sheer volume of mergers -- I cannot talk more on this subject. So, let me tell you, LIGO actually never detected any black hole mergers in the past too.

Sep 20, 2017
Oh swell, the plasma ignoramuses are proposing a pair of dancing unicorns as the progenitors of the radio sources. It's obvious these "scientists" wouldn"t know their plasma processes from a hole in the ground.

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