The first confirmed “heartbeat” of a supermassive black hole is still going strong more than a decade after first being observed, according to Chinese and British astronomers.
That makes it the longest-lived ever seen in a black hole, they say, and tells us more about the size and structure close to its event horizon – the space around a black hole from which nothing, including light, can escape.
Writing in Monthly Notices of the Royal Astronomical Society, researchers from the Chinese Academy of Sciences and Durham University report that X-ray satellite observations spotted the repeated beat after its signal was blocked by our Sun for a number of years.
“This heartbeat is amazing,” says lead author Chichuan Jin. “It proves that such signals arising from a supermassive black hole can be very strong and persistent.”
The Quasi-Periodic Oscillations (QPO) were first detected in 2007 at the centre of a galaxy called RE J1034+396, which is approximately 600 million light-years from Earth.
The signal repeated every hour, and this was seen in several snapshots taken before satellite observations were blocked by the Sun in 2011.
In 2018 the European Space Agency’s XMM-Newton X-ray satellite was able to finally re-observe the black hole and to scientists’ amazement the same repeated heartbeat could still be seen.
Matter falling on to a supermassive black hole as it feeds from the accretion disc of material surrounding it releases an enormous amount of power from a comparatively tiny region of space, but this is rarely seen as a specific repeatable pattern like a heartbeat.
The time between beats can tell us about the size and structure of the matter close to the black hole’s event horizon.
“The main idea for how this heartbeat is formed is that the inner parts of the accretion disc are expanding and contracting,” says Durham’s Chris Done.
“The only other system we know which seems to do the same thing is a 100,000 times smaller stellar-mass black hole in our Milky Way, fed by a binary companion star, with correspondingly smaller luminosities and timescales.
“This shows us that simple scalings with black hole mass work even for the rarest types of behaviour.”
Model for the Quasi-Periodic Oscillations, shown as a cross-section in the plane of the disc. Credit: Chichuan Jin, Chinese Academy of Sciences.
Originally published by Cosmos as Black hole’s heart still beating strongly
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