Gemma Conroy * says scientists have accidentally discovered a black hole so large that you can detect it with a telescope in the backyard.
Black holes are the gluttons of the cosmos, which devour everything that comes too close, including light itself.
Now, an international team of researchers says they have discovered a supermassive black hole that devours the equivalent of one Earth every second.
Looking at other bright objects that are billions of years old, the team confirmed that the newly discovered giant was the brightest, fastest-growing supermassive black hole in the last 9 billion years (as we know it).
Located in the bright constellation Centaurus, this luminous cosmic beast is more than 500 times larger than the supermassive black hole in the center of our own galaxy.
The findings, which are currently under review, were published last week on arXiv.
“People have been looking for this kind of object since the 1960s,” said lead author Christopher Onken, an astronomer at the National University of Australia.
“And somehow, this one seemed to have escaped all our previous efforts to find it.”
A needle in a haystack
The team stumbled upon the unusual object as they searched for nearby pairs of binary stars, the stars orbiting around the same center of mass, in the Milky Way.
They were using the SkyMapper telescope at the Siding Spring Observatory near Coonabarabran, between the central west and north-west regions of New South Wales.
Adrian Lucy, a doctoral student at Columbia University in New York, found about 200 binary star candidates, but there was something strange about them, according to Dr. Onken.
“One of them turned out to be something that bore no resemblance to a binary system.”
To take a closer look at the strange object, the team went to the 1.9-meter telescope at the South African Astronomical Observatory in Cape Town.
Here, they were able to observe the different wavelengths of light coming from the object, which they called SMSS J114447.77-430859.3, or J1144 for short.
“You really see the detailed fingerprints of what these objects form,” Dr. Onken said.
And it didn’t look like a giant star.
Instead, the object had bright lines suggesting that the gas was moving very fast, indicating that it was fed by a supermassive black hole.
Supermassive black holes, which have a mass of millions or billions of Suns, are the engines that drive some of the brightest objects in the sky: quasars.
From Earth, these luminous objects look a bit like stars, but their light comes from the ring of gas, dust, and stars that revolves around the black hole, known as the accretion disk.
As this material is sucked into the open mouth of the black hole by its intense gravitational pull, it heats up a lot and emits bright light.
“The gas is being channeled in the form of pancakes, and this material is heated by friction,” Dr. Onken said.
Like a ball rolling down a hill, the material moves faster as it approaches the black hole’s event horizon, the point where not even light can escape, yielding its potential energy.
“Eventually, all of these things fall into the black hole beyond the event horizon, increasing the mass of the black hole as it does so.”
It was this bright, fast-moving gas vortex that allowed Dr. Onken and his team to measure the mass of the supermassive black hole: an estimated 3,000 million suns.
To put it in perspective, the supermassive black hole in the center of our galaxy, Sagittarius A *, has a mass of about 4 million Suns.
And while J1144 was weaker than other quasars identified over the past 60 years, it was much farther away and still much brighter than other objects of a similar age.
“It was very exciting because it’s a very unusual find,” Dr. Onken said.
It shines like a black hole
The team also compared the brightness of the J1144 over the past 45 years looking at how it appeared in previous datasets.
They found that the giant quasar had remained consistently bright over time, indicating that its black hole was constantly chewing gas and anything else that came up.
Michael Cowley, an astrophysicist at Queensland University of Technology, said the size of the supermassive black hole probably meant it was associated with a strong galaxy.
“In general, you’ll find that the more massive the black hole, the more massive the galaxy is,” said Dr. Cowley, who did not participate in the study.
The light from this quasar shines about 7,000 times brighter than all the light in the Milky Way, which means you can see it from your garden with the right telescope.
Dr. Onken said you will need a 30-40 cm diameter telescope and a camera that can do long exposures.
J1144 is located just northwest of the Southern Cross in the sky, shining from the constellation Centaurus.
“It’s just over at dusk at this time of year,” Dr. Onken said.
A practical galactic tool
Dr. Cowley said the rare finding could provide tempting clues about the formation and evolution of galaxies.
“This is because the different properties of the supermassive black hole and its host galaxy are correlated.
“By studying black holes, we can understand the galaxy and vice versa.”
Although J1144 is outside the Milky Way, Dr. Cowley said its relatively close proximity could make it a useful tool for understanding how gas moves in and out of our own galaxy.
“If you imagine the Milky Way as a relatively flat spiral disk galaxy, the location where they saw this thing is pretty close to the galaxy’s disk,” Dr. Cowley said.
Dr. Onken and his team also want to get to the bottom of what led to the monstrous J1144 in the first place, along with finding out what else has been hidden from view.
“We don’t know if this object is a late bloom, or if it has had a major galaxy collision that has suddenly been able to launch all this gas into the black hole to feed it,” he said.
“This has really sparked a new round of research to see what other objects have been lost in all surveys over the years.”
* Gemma Conroy is a science reporter in the RN Science Unit.
This article first appeared on abc.net.au.