Scientists Discover Black Hole Has Three Hot Meals a Day

NASA — Chandra X-ray Observatory patch.

Sept. 11, 2019

There’s an adage that it’s not healthy to skip meals. Apparently, a supermassive black hole in the center of a galaxy millions of light years away has gotten the message.

A team of astronomers found X-ray bursts repeating about every nine hours originating from the center of a galaxy called GSN 069. Obtained with NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM-Newton, these data indicate that   the supermassive black hole located there is consuming large amounts of material on a regular schedule.

While scientists had previously found two “stellar-mass” black holes (that weigh about 10 times the Sun’s mass) occasionally undergoing regular outbursts before, this behavior has never been detected from a supermassive black hole until now.

The black hole at the center of GSN 069, located 250 million light years from Earth, contains about 400,000 times the mass of the Sun. The researchers estimate that the black hole is consuming about four Moons’ worth of material about three times a day. That’s equivalent to almost a million billion billion pounds going into the black hole per feeding.

“This black hole is on a meal plan like we’ve never seen before,” said Giovanni Miniutti from ESA’s Center for Astrobiology in Spain, the first author of a Nature paper, published today, describing these results. “This behavior is so unprecedented that we had to coin a new expression to describe it: “X-ray Quasi-Periodic Eruptions”.”

ESA’s XMM-Newton was the first to observe this phenomenon in GSN 069 with the detection of two bursts on December 24, 2018. Miniutti and colleagues then followed up with more XMM-Newton observations on January 16 and 17, 2019, and found five outbursts. Observations by Chandra less than a month later, on February 14, revealed an additional three outbursts.

“By combining data from these two X-ray observatories, we have tracked these periodic outbursts for at least 54 days” said co-author Richard Saxton of the European Space Astronomy Centre in Madrid, Spain. “This gives us a unique opportunity to witness the flow of matter into a supermassive black hole repeatedly speeding up and slowing down.”


During the outbursts the X-ray emission becomes about 20 times brighter than during the quiet times. The temperature of gas falling towards the black hole also climbs, from about one million degrees Fahrenheit during the quiet periods to about 2.5 million degrees Fahrenheit during the outbursts. The temperature of the latter is similar to that of gas found around most actively growing supermassive black holes.

The origin of this hot gas has been a long-standing mystery because it appears to be too hot to be associated with the disk of infalling matter surrounding the black holes. Although its origin is also a mystery in GSN 069, the ability to study a supermassive black hole where hot gas repeatedly forms then disappears may provide important clues.

“We think the origin of the X-ray emission is a star that the black hole has partially or completely torn apart and is slowly consuming bit by bit.” said co-author Margherita Giustini, also of ESA’s Center for Astrobiology. “But as for the repeating bursts, this is a completely different story whose origin needs to be studied with further data and new theoretical models”.

The consumption of gas from a disrupted star by a supermassive black hole has been observed before, but never accompanied by repetitive X-ray bursts. The authors suggest there are two possible explanations for the bursts. One is that the amount of energy in the disk builds up until it becomes unstable and matter rapidly falls into the black hole producing the bursts. The cycle would then repeat. Another is that there is an interaction between the disk and a secondary body orbiting the black hole, perhaps the remnant of the partially disrupted star.



The Chandra data were crucial for this study because they were able to show that the X-ray source is located in the center of the host galaxy, which is where a supermassive black hole is expected to be. The combination of data from Chandra and XMM-Newton implies that the size and duration of the black hole’s meals have decreased slightly, and the gap between the meals has increased. Future observations will be crucial to see if the trend continues.

Chandra X-ray Observatory



Supermassive black holes are usually larger than GSN 069, with masses of millions or even billions of suns. The larger the black hole the slower their fluctuations in brightness will be, so instead of erupting every nine hours they should erupt every few months or years which likely explains why quasi-periodic eruptions where never seen before.

Examples of large increases or decreases in the amount of X-rays produced by black holes have been observed in a few cases, using repeated observations over months or even years. The changes in some objects are much faster than expected by standard theory of disks of infalling matter surrounding black holes, but could be naturally accounted for if they were experiencing similar behavior to GSN 069.

Along with data from Chandra and XMM-Newton the international research team used data from NASA’s Swift X-ray observatory, the NASA/ESA Hubble Space Telescope, NRAO’s Karl G. Jansky Very Large Array in New Mexico, USA, CSIRO’s Australia Telescope Compact Array in Australia, and SARAO’s MeerKAT radio telescope in South Africa.

This paper appears in the September 11, 2019 issue of the journal Nature. NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science and flight operations from Cambridge, Massachusetts.

Read more from NASA’s Chandra X-ray Observatory: https://chandra.harvard.edu/photo/2019/gsn069/index.html

For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra

Image, Animation, Text, Credits: X-ray: NASA/CXO/CSIC-INTA/G.Miniutti et al.; Optical: DSS/NASA/Lee Mohon.

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Unexpected periodic flares may shed light on black hole accretion

XMM-Newton observations
Copyright: ESA/XMM-Newton; G. Miniutti & M. Giustini (CAB, CSIC-INTA, Spain)

ESA’s X-ray space telescope XMM-Newton has detected never-before-seen periodic flares of X-ray radiation coming from a distant galaxy that could help explain some enigmatic behaviours of active black holes.

XMM-Newton, the most powerful X-ray observatory, discovered some mysterious flashes from the active black hole at the core of the galaxy GSN 069, about 250 million light years away. On 24 December 2018, the source was seen to suddenly increase its brightness by up to a factor 100, then dimmed back to its normal levels within one hour and lit up again nine hours later.

“It was completely unexpected,” says Giovanni Miniutti, of the Centro de Astrobiología in Madrid, Spain, lead author of a new paper published in the journal Nature today.

“Giant black holes regularly flicker like a candle but the rapid, repeating changes seen in GSN 069 from December onwards are something completely new.”

Further observations, performed with XMM-Newton as well as NASA’s Chandra X-ray observatory in the following couple of months, confirmed that the distant black hole was still keeping the tempo, emitting nearly periodic bursts of X-rays every nine hours. The researchers are calling the new phenomenon ‘quasi-periodic eruptions’, or QPEs.

Optical and X-ray view

Copyright X-ray: NASA/CXO/CSIC-INTA/G.Miniutti et al.; Optical: DSS

“The X-ray emission comes from material that is being accreted into the black hole and heats up in the process,” explains Giovanni.

“There are various mechanisms in the accretion disc that could give rise to this type of quasi-periodic signal, potentially linked to instabilities in the accretion flow close to the central black hole.

“Alternatively, the eruptions could be due to the interaction of the disc material with a second body – another black hole or perhaps the remnant of a star previously disrupted by the black hole.”

Although never before observed, Giovanni and colleagues think periodic flares like these might actually be quite common in the Universe.

It is possible that the phenomenon had not been identified before because most black holes at the cores of distant galaxies, with masses millions to billions of times the mass of our Sun, are much larger than the one in GSN 069, which is only about 400 000 times more massive than our Sun.

The bigger and more massive the black hole, the slower the fluctuations in brightness it can display, so a typical supermassive black hole would erupt not every nine hours, but every few months or years. This would make detection unlikely as observations rarely span such long periods of time.

And there is more. Quasi-periodic eruptions like those found in GSN 069 could provide a natural framework to interpret some puzzling patterns observed in a significant fraction of active black holes, whose brightness seems to vary too fast to be easily explained by current theoretical models.

“We know of many massive black holes whose brightness rises or decays by very large factors within days or months, while we would expect them to vary at a much slower pace,” says Giovanni.

“But if some of this variability corresponds to the rise or decay phases of eruptions similar to those discovered in GSN 069, then the fast variability of these systems, which appears currently unfeasible, could naturally be accounted for. New data and further studies will tell if this analogy really holds.”

Quasi-periodic eruptions in GSN 069
Copyright ESA/XMM-Newton; NASA/CXC; G. Miniutti (CAB, CSIC-INTA, Spain)

The quasi-periodic eruptions spotted in GSN 069 could also explain another intriguing property observed in the X-ray emission from nearly all bright, accreting supermassive black holes: the so-called ‘soft excess’.

It consists in enhanced emission at low X-ray energies, and there is still no consensus on what causes it, with one leading theory invoking a cloud of electrons heated up near the accretion disc.

Like similar black holes, GSN 069 exhibits such a soft X-ray excess during bursts, but not between eruptions.

“We may be witnessing the formation of the soft excess in real time, which could shed light on its physical origin,” says co-author Richard Saxton from the XMM-Newton operation team at ESA’s astronomy centre in Spain.

“How the cloud of electrons is created is currently unclear, but we are trying to identify the mechanism by studying the changes in the X-ray spectrum of GSN 069 during the eruptions.”

The team is already trying to pinpoint the defining properties of GSN 069 at the time when the periodic eruptions were first detected to look for more cases to study.

«One of our immediate goals is to search for X-ray quasi-periodic eruptions in other galaxies, to further understand the physical origin of this new phenomenon,” adds co-author Margherita Giustini of Madrid’s Centro de Astrobiología.

“GSN 069 is an extremely fascinating source, with the potential to become a reference in the field of black hole accretion,” says Norbert Schartel, ESA’s XMM-Newton project scientist.

The discovery would not have been possible without XMM-Newton’s capabilities.

“These bursts happen in the low energy part of the X-ray band, where XMM-Newton is unbeatable. We will certainly need to use the observatory again if we want to find more of these kinds of events in the future,” concludes Norbert.


Notes for editors

Nine-hour X-ray quasi-periodic eruptions from a low-mass black hole galactic nucleus’ by G. Miniutti et al. is published in Nature. DOI: 10.1038/s41586-019-1556-x

The international research team used astronomical data from ESA’s XMM-Newton, NASA’s Chandra and Swift X-ray observatories, the NASA/ESA Hubble Space Telescope, NRAO’s Karl G. Jansky Very Large Array in New Mexico, USA, CSIRO’sAustralia Telescope Compact Array in Australia, and SARAO’sMeerKAT radio telescope in South Africa.


For more information, please contact:

Giovanni Miniutti
Centro de Astrobiología (CAB, CSIC-INTA)
Madrid, Spain
Email: gminiutti@cab.inta-csic.es

Richard Saxton
Telespazio-Vega UK for ESA
XMM-Newton Science Operations Centre
European Space Agency
Email: richard.saxton@sciops.esa.int

Margherita Giustini
Centro de Astrobiología (CAB, CSIC-INTA)
Madrid, Spain
Email: mgiustini@cab.inta-csic.es

Norbert Schartel
XMM-Newton project scientist
European Space Agency
Email: norbert.schartel@sciops.esa.int


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HiPOD 11 September 2019: The Earth and Moon as Seen from MarsA…

HiPOD 11 September 2019: The Earth and Moon as Seen from Mars

A special repost of an image we took in 2007:

“They shall grow not old, as we that are left grow old:
Age shall not weary them, nor the years condemn.
At the going down of the sun and in the morning,
We will remember them.”
Laurence Binyon

NASA/JPL/University of Arizona