The black hole burst hundreds of millions of years ago, leaving behind an unprecedented lyncan of “empty fossils.”

In the deep sky, about 390 million light-years from Earth, a behemoth is sitting in the Constellation of Serpentine Galaxy. If we take our common X-ray observations, it is the second brightest cluster of galaxies ever discovered by humans, after the Enceladus cluster 300 million light-years away. In recent years, astronomers have been digging out the secrets behind this bright pearl for hundreds of millions of years.

Recent lying by astronomers in the United States and Australia, a team of astronomers, found that the huge, mysterious gas cavity previously observed in the Serpentine galaxy cluster was caused by the eruption of a massive black hole in the center of the galaxy cluster long before. In other words, the central black hole violently releases energy and “smashes” a huge hole around it, about 1.5 million light-years in diameter, and can hold 15 contin lines of the Milky Way. The findings were published in the astrophysical journal.

Simone Giasintucci, the first author of the paper and a researcher at the U.S. Naval Research Institute, likened the hole to a “huge radio fossil” for a long time.

Misty, explore the source of energy

Similar voids have been found in other galaxy clusters before, such as the aforementioned Insani galaxy cluster and the Constellation A galaxy cluster, the researchers said. But the hollowness of the cluster of galaxies in the constellation Serpentine is unprecedented. They estimate that the energy needed to make the hole could be six times as much as the largest known hole of its kind. One billion solar emits less than one percent of the energy that causes the explosion.

How exactly did the hole come into being? Based on previous studies, it is possible to cause the nucleus of an active galaxy.

Active galactic nuclei refer to the active outer galactic cores of a central core region, which are active and bright. The “engine” of the active galactic nucleus is generally thought to be a supermassive black hole. A black hole attracts matter and forms a constantly rotating accretion disk around it. The matter in the accretion disk continues to fall into the black hole, the angular momentum of the material loss, in the form of energy is “spitout” by the black hole, forming a high-speed jet stream in the vertical direction of the accretion disk.

In previous studies, the central black hole that is erupting has been observed, whether in the constellation of Enceladus or in other galaxy clusters. The black hole’s jet stream, like a bright beam of light in the dark, carries enormous amounts of energy that heat and “expel” the dispersed gas around it, creating a similar hollow.

However, the mystery of the source of energy in the serpentine’s hollow is a twist.

As early as 2006, the snake’s cavity came to the attention of researchers. Lu Yujun, a researcher at the National Observatory of the Chinese Academy of Sciences, told Science and Technology Daily that another group of researchers, using X-ray data from the Chandra Space Telescope, found a “strange curve” in the Serpentine galaxy cluster, the edge of the hole. But what is puzzling is that the black hole in the center of the Serpentine galaxy cluster is very dark and silent, and there is no sign of an explosion. On the other hand, the researchers believed that the energy needed to create the hole was too great, thus denying the possibility that a black hole would erupt and cause the hole to form.

Now, why are black holes-dengined active galaxies now being blamed as “the culprits”?

“The study used radio-band data from which researchers found high-energy relativistic electrons, from which black hole jets can produce these high-energy electrons directly and on a large scale. Chen Xuelei, a researcher at the National Observatory of the Chinese Academy of Sciences, told Science and Technology Daily that the 2006 study relied heavily on X-ray data, limited to the band region, unable to detect relativistic electrons, and only relatively low-energy electrons, which were sourced from both the central black hole of the galaxy cluster. Other astronomical events, such as galaxy clusters and integration activities. Therefore, under the support of the research data of the year, the source of energy formed by the snake’s cavity is not clear.

“If the results of this study are true, the enigmatic balance will tilt toward the end of the ‘central black hole outbreak’. Chen Xuelei said.

Silence, waiting for the next round

In Chen Xuelei’s view, this may not be the result of a one-time brief burst of black holes in the central black hole of the Constellation of Serpentine, probably after tens of millions of years or even hundreds of millions of years of accumulation, to show what is now seen as a huge hole.

Unfortunately, the galactic nucleus of the Serpentine galaxy cluster has become “lazy”, the central black hole has calmed down, the signal released by the central core region is very weak, and future generations may not be able to appreciate the “fireworks” of the central core of the Serpentine galaxy cluster for a lifetime.

What causes the active galactic nucleus to fall silent? Chen said available data suggest that the active galaxy’s nuclear activity could last tens to hundreds of millions of years. The nucleus of the galaxy is active by absorbing energy from the surrounding material, which in turn, the black hole jet will blow away the surrounding material, and over time, when all the matter around the black hole is dispersed into the distance, the black hole will “starve to death” and the active galactic nucleus will fall silent. After a long evolution, the scattered matter is re-attracted by the black hole, which opens up the next cycle.

“Thus, the silence after the explosion of the active galactic nucleus is inevitable, but humans only a few decades ago have the corresponding means of observation, in the time scale of human activities to observe the active galactic nucleus to stop the entire process.” Chen Xuelei said.

Although the nucleus of the galaxy in the Constellation of Serpentine is no longer active, the huge void it creates has not yet dissipated, helping us restore the history of the starry sky hundreds of millions of years ago. The effects of this ancient eruption are far more profound than the hollow appearances we have observed.

“The explosion of the nucleus of an active galaxy can inhibit star formation to some extent. Lu pointed out that the birth of stars is closely related to the high density of cooling gases in the universe, and that black hole jets heat the surrounding gas, in part hindering the pace of star birth. This phenomenon is known as the active galactic nuclear feedback effect.

“Family” Tintin, more puzzles to solve

“This study of the Serpentine galaxy cluster sits a case of a large family of large hollows caused by the active galactic nucleus in the cluster, and helps us study the core of the galaxy formation process, namely, the active galactic nucleus feedback effect.” Lu by Jun Dao.

Unlike similar events in the past, the researchers observed a cold core inside the serpentine cluster, where energy from the cold core to the core plummeted from 10keV to below 1keV, and the temperature dropped sharply. Cold cores tend to be destroyed by high-temperature jets when black holes erupt.

In Lu’s view, the snake-like cluster of galaxies after the explosion of the galactic nucleus into a long period of silence, the galaxy cluster of gas less energy injection, only led to the formation of the cold core. “Thus, this study is also useful for the study of internal heating and cooling of galaxy clusters, and thus to understand the early active galactic nucleus feedback process of the constellation Serpentine.” “

The sky is vast and the exploration is endless.

Lu said there are still some problems that need to be studied in depth in response to the hollowing of the galaxy in the constellation serpentine. For example, to further understand the specific size of the central black hole in the constellation Serpentine galaxy cluster, it can be estimated whether the black hole can produce enough energy to form this huge hole. Moreover, it needs further proof whether the jet stream, which is “besieged” by many galaxy clusters, can be emitted into the hollow position and retains huge amounts of energy, which needs further proof.

The study used radio information collected by the Murchison Wide Field Array in Australia and India’s Jumbo Wave Radio Telescope. “With the development of low-frequency radio telescopes and more new observation al-Tech, it is believed that more and more similar phenomena will be observed and more exotic astronomical landscapes awaiting excavation and exploration.” Chen Xuelei said.