Huge black hole blasts out ‘double burp’

Astronomers have caught a massive black hole letting out a “double burp” after bingeing on hot gas.

When cosmic gas comes near one of these sinkholes, it gets sucked in – but some of the energy is released back into space in the form of a burp.

Now, the Hubble and Chandra space telescopes have detected a new belch emerging from a black hole located about 800 million light-years away.

But they saw a remnant of another belch that occurred 100,000 years earlier.

“Black holes are voracious eaters, but it turns out they don’t have very good table manners,” Julie Comerford, from the University of Colorado, Boulder, told the 231st American Astronomical Society meeting in Washington DC.

“There are a lot of examples of black holes with single burps emanating out, but we discovered a galaxy with a supermassive black hole that has not one but two burps.”

The burp itself consists of a stream of high-energy particles that is kicked back from the black hole.

Supermassive black holes are the largest type and are found at the centres of nearly all big galaxies. X-ray emission from the galaxy in question – called SDSS J1354+1327 – was picked up by the Chandra telescope, allowing researchers to pinpoint the location of its central black hole.

Hubble was able to show them that a cloud of blue-green gas extending away from the black hole represented the aftermath of an earlier burp. They found that electrons had been stripped from atoms in the cone of gas and surmise that this was caused by a burst of radiation from the vicinity of the black hole.

In the meantime, it had expanded 30,000 light-years away from the black hole itself.

But the astronomers found a little loop in the images; the sign of a new belch emerging from the cosmic sinkhole.

“This new burp is actually moving like a shockwave that is coming out very fast,” said Dr Comerford.

“I thought of an analogy for this and I was debating whether to use it or whether it’s a little too gross… imagine someone eating dinner at their kitchen table and they’re eating and burping, eating and burping.

“You walk in the room and you notice there’s an old burp still hanging in the air from the appetiser course. Meanwhile, they’re eating the main course and they let out a new burp that’s rocking the kitchen table.”

She said the black hole was going through a cycle of feasting, burping and napping, before starting over.

The observations are important because they support previous theories – not demonstrated until now – that black holes should go through these cycles. The black holes were expected to become very bright in the process of feasting and burping and then go dark during the nap phase.

“Theory predicted that black holes should flicker on and off very quickly and this galaxy’s evidence of black holes does flicker on timescales of 100,000 years – which is long in human timescales, but in cosmological timescales is very fast,” said Julie Comerford.

The researchers think the black hole erupted twice because it consumed two separate meals. The reason for this might lie with the fact that the galaxy it’s in had collided with another galaxy nearby. This would provide plenty of cosmic gas on which a black hole could feast.

“There’s a stream of stars and gas connecting these two galaxies. That collision led gas to stream towards the supermassive black hole and feed it two separate meals that led to these two separate burps,” said the University of Colorado researcher.

The results are published in the Astrophysical Journal.

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Farthest monster black hole found

Astronomers have discovered the most distant “supermassive” black hole known to science.

The matter-munching sinkhole is a whopping 13 billion light-years away, so far that we see it as it was a mere 690 million years after the Big Bang.

But at about 800 million times the mass of our Sun, it managed to grow to a surprisingly large size in just a short time after the origin of the Universe.

The find is described in the journal Nature.

The newly discovered black hole is busily devouring material at the centre of a galaxy – marking it out as a so-called quasar.

Matter, such as gas, falling onto the black hole will form an ultra-hot mass of material orbiting around it known as an accretion disk.

“Quasars are among the brightest and most distant known celestial objects and are crucial to understanding the early Universe,” said co-author Bram Venemans of the Max Planck Institute for Astronomy in Germany.

This quasar is interesting because it comes from a time when the Universe was just 5% of its current age.

At this time, the cosmos was beginning to emerge from a period known as the dark ages – just before the first stars appeared.

“Gathering all this mass in under 690 million years is an enormous challenge for theories of supermassive black hole growth,” said co-author Eduardo Bañados, from the Carnegie Institution for Science.

The quasar’s distance is described by a property called its redshift – a measurement of how much the wavelength of its light is stretched by the expansion of the Universe before reaching Earth.

The newly discovered black hole has a redshift of 7.54. The higher the redshift, the greater the distance, and the farther back astronomers are looking in time when they observe the object.

Prior to this discovery, the record-holder for the furthest known quasar existed when the Universe was about 800 million years old.

“Despite extensive searches, it took more than half a decade to catch a glimpse of something this far back in the history of the Universe,” said Dr Bañados.

The discovery of a massive black hole so early on may provide key clues on conditions that abounded when the Universe was young.

“This finding shows that a process obviously existed in the early Universe to make this monster,” Dr Bañados explained.

“What that process is? Well, that will keep theorists very busy.”

The unexpected discovery is based on data amassed from observatories around the world. This includes data from the Gemini North observatory on Hawaii’s Maunakea volcano and a Nasa space telescope called the Wide-field Infrared Survey Explorer (Wise).

Event Horizon Telescope ready to image black hole

Scientists believe they are on the verge of obtaining the first ever picture of a black hole.

They have built an Earth-sized “virtual telescope” by linking a large array of radio receivers – from the South Pole, to Hawaii, to the Americas and Europe.

There is optimism that observations to be conducted during 5-14 April could finally deliver the long-sought prize.

In the sights of the so-called “Event Horizon Telescope” will be the monster black hole at the centre of our galaxy.

Although never seen directly, this object, catalogued as Sagittarius A*, has been determined to exist from the way it influences the orbits of nearby stars.

These race around a point in space at many thousands of km per second, suggesting the hole likely has a mass of about four million times that of the Sun.

But as colossal as that sounds, the “edge” of the black hole – the horizon inside which an immense gravity field traps all light – may be no more than 20 million km or so across.

And at a distance of 26,000 light-years from Earth, this makes Sagittarius A* a tiny pinprick on the sky.

The Event Horizon Telescope (EHT) team is nonetheless bullish.

“There’s great excitement,” said project leader Sheperd Doeleman from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.

“We’ve been fashioning our virtual telescope for almost two decades now, and in April we’re going to make the observations that we think have the first real chance of bringing a black hole’s event horizon into focus,” he told BBC News.

The EHT’s trick is a technique called very long baseline array interferometry (VLBI).

This combines a network of widely spaced radio antennas to mimic a telescope aperture that can produce the resolution necessary to perceive a pinprick on the sky.

The EHT is aiming initially to get down to 50 microarcseconds. Team-members talk in analogies, describing the sharpness of vision as being the equivalent of seeing something the size of a grapefruit on the surface of the Moon.

They emphasise the still complex years of work ahead, but also trail the prospect of an imminent breakthrough.

The scientists certainly have an expectation of what they ought to see, if successful.

Simulations rooted in Einstein’s equations predict a bright ring of light fringing a dark feature.

The light would be the emission coming from gas and dust accelerated to high speed and torn apart just before disappearing into the hole.

The dark feature would be the shadow the hole casts on this maelstrom.

“Now, it could be that we will see something different,” Doeleman said.

“As I’ve said before, it’s never a good idea to bet against Einstein, but if we did see something that was very different from what we expect we would have to reassess the theory of gravity.

“I don’t expect that is going to happen, but anything could happen and that’s the beauty of it.”

Over the years, more and more radio astronomy facilities have joined the project. A key recent addition is the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.

Its extraordinary state-of-the-art technology has at a stroke increased the EHT’s sensitivity by a factor of 10. Hence, the optimism ahead of April.

Even so, scientists have had to install special equipment at all the radio facilities involved in the observations.

This includes big hard drives to store colossal volumes of data, and atomic clocks to precisely timestamp it all.

Nothing happens on the spot – the hard drives must first be flown to a large computing facility at MIT Haystack Observatory in Westford, just outside Boston, Massachusetts.

“Our hard-drive modules hold the capacity of about 100 standard laptops,” said Haystack’s Vincent Fish.

“We have multiple modules at each telescope and we have numerous telescopes in the array. So, ultimately, we’re talking about 10,000 laptops of data.”

It is in Haystack’s correlator computer that the synthesis will begin.

Some very smart imaging algorithms have had to be developed to make sense of the EHT’s observations, but it will not be a quick result.

It could be the end of the year, perhaps the start of 2018, before the team releases an image in public.

Looking to the future, the scientists are already thinking about how to extend their techniques.

For example, the matter closest to the event horizon and about to disappear into Sagittarius A* should take about 30 minutes to complete an orbit.

Katie Bouman, from MIT’s Computer Science and Artificial Intelligence Laboratory, thinks it might be possible to capture this movement.

“We want to push boundaries and to try to make movies from the data,” she told BBC News.

“Maybe we can actually see some of the gas flowing around the black hole. That’s really the next stage of what we’re trying to accomplish with these imaging algorithms.”

First and foremost, the team needs good weather at the participating observing stations in April.

The strategy is to view the galactic centre at a wavelength of 1.3mm (230GHz). This has the best chance of piercing any obscuring gas and dust in the vicinity of the black hole. But if there is too much water vapour above the array’s receivers, the EHT will struggle even to see through Earth’s atmosphere.

Just getting a resolved view of Sagittarius A* would be a remarkable triumph in itself. But the real objective here is to use the imaging capability to go test aspects of general relativity.

If there are flaws to be found in Einstein’s ideas – and scientists suspect there are more complete explanations of gravity out there waiting to be discovered – then it is in the extreme environment of black holes that limitations should be exposed. and follow me on Twitter: @BBCAmos