Astronomers find a supermassive black hole that reigns on a regular schedule, every 9 hours

Astronomers have discovered a supermassive black hole (SMBH) with an unusually regular feeding schedule. Behemoth is an active galactic nucleus (AGN) located in the heart of the Seyfert 2 galaxy, GSN 069. It is located about 250 million light years from Earth and contains about 400,000 times the mass of the Sun.

The team of astronomers used ESA's Chandra X-ray observatory, ESA's XMM-Newton, and NASA to observe the SMBH's X-ray emissions. Every 9 hours or so, the black hole fires X-rays as materials are sucked into them. Astronomers have discovered two other star-mass black holes that flare up regularly while feeding, but this kind of regularity in a supermassive black hole has never been seen before.

"This black hole is on a meal plan like we've never seen before."

Giovanni Miniutti, Senior Author, ESA Astrobiology Center, Spain.

The document describing this discovery is published in Nature and titled "Nine-Hour Quasi-periodic X-Ray Eruptions from a Galactic Core of Low Mass Black Hole." The main author is Giovanni Miniutti of the Center for Astrobiology of ESA in Spain. According to the newspaper, the SMBH consumes about four times the moon's material three times a day. This means that every time the black hole feeds, it consumes about one trillion billion pounds of materials.

"This black hole is on a meal plan like we had never seen before," Miniutti said in a press release. "This behavior is so unprecedented that we had to invent a new expression to describe it:" quasi-periodic x-ray eruptions. "

The X-ray emissions of this SMBH have been known and observed since July 2010, but have remained stable. The new document builds on 54 days of observations starting in December 2018, starting with the ESA's XMM-Newton observatory. This observatory spotted two bursts on December 24th. In January, XMM-Newton found three more of these regular bursts.

Astronomers then asked for more observation time with NASA's Chandra Observatory to investigate. Chandra observed five more of these events. During ongoing regular eruptions, X-ray flaring activity increases by two orders of magnitude compared to background X-ray emissions. Each push lasts a little over an hour and occurs every nine hours.

"By combining the data from these two X-ray observatories, we followed these periodic explosions for at least 54 days," said co-author Richard Saxton of the European Space Astronomy Center in Madrid, Spain. . "This gives us a unique opportunity to witness the flow of material in a supermassive black hole that accelerates and slows down repeatedly."

In each of these explosions, X-rays are 20 times brighter than during quiet periods. The incoming gas temperature also increases. It goes from about 1 million degrees Fahrenheit during quieter periods to 2.5 million degrees Fahrenheit during flares. The higher temperature is about the same as the gas temperature around most actively growing SMBHs.

The cause of these regular outbreaks is unknown. The 2.5 million degrees F. hot gas surrounding the GSN 069 is the same temperature as the gas surrounding the other SMBHs. It's a mystery because it's just too hot to come from the disc of material that surrounds the black holes. But GSN 069 is a unique opportunity to study the phenomenon because the hot gas is formed repeatedly and then disappears.

Normally, this hot gas is caused by a star torn and consumed by a black hole, at least that is what astronomers think. But the regularity presented by GSN 069 is a mystery.

"We believe that the origin of X-ray emission is a star that the black hole has partially or completely torn and consumes slowly, little by little," said co-author Margherita Giustini, also from the Center for Astrobiology from ESA. "But with regard to repeated bursts, it's a completely different story whose origin has to be studied with additional data and new theoretical models."

Again, seeing a supermassive black hole consuming gas from a star is nothing new. It is the regularity of the blaze of GSN 069 which makes creak the head. The authors of the study suggest two possible explanations of the SMBH's regular feeding program:

• The amount of energy contained in the disc accumulates until it becomes unstable and the material quickly falls into the black hole that produces the chips. This cycle is repeated.
• There is an interaction between the disk and a secondary body orbiting the black hole, perhaps the rest of the partially disturbed star.

Thanks to Chandra's observations, the team of scientists knows that the source of incandescent X-rays lies at the heart of the GSN 069. This is where a SMBH should be. The combined data from Chandra and XMM-Newton also clearly show that flaring, although regular, is slowly changing: the size and duration of the "meals" of the black hole have decreased slightly and the space between each meal is increasing. It is up to future observations to see if these trends continue.

GSN 069 is rather small for a SMBH. Usually, a SMBH contains as many as several million or even billions of suns, while GSN 069 contains only about 400,000 suns. This could help explain why this type of regular diet has not been seen before.

For larger SMBHs, much larger than this, their brightness fluctuations are much slower. Rather than bursting every nine hours, it should take them months, if not years, to burn out like that. This would explain why quasi-periodic eruptions such as these have not been observed. X-ray observatories are busy and there is no way to train them on a single target for as long.

There have been several cases of significant increase or decrease in X-rays produced by black holes. These observations were based on repeated observations over months or even years. Some of these changes are too fast to be explained by the standard theory of suspended matter from the accretion disk of a black hole. But this discovery could explain these observations. They may behave similarly to GSN 069.

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