Malcarian 817 is how a grumpy black hole reshaped its galaxy

Mondo Science Updated on 2024-02-14

Black holes are one of the most mysterious objects in the universe, and their strong gravitational pull can swallow the matter around them, while also influencing the evolution of the galaxies in which they are located. Recently, scientists discovered a distant black hole that behaves unusually violently, not only ejecting large amounts of material out, but also creating an empty area in its galaxy where almost no new stars are born. This astonishing phenomenon reveals to us how black holes shape our own galaxies and may even explain a mystery at the center of our galaxy.

This black hole is located at the center of the spiral galaxy Marcarian 817, which is about 4300 million light years. That said, the Malcarian 817 we see is that it is in 4What it looked like 300 million years ago, before dinosaurs appeared on Earth. The black hole of Marcarian 817 is huge, about 10 million times more massive than the Sun. Like our own galaxy, its black hole is an important force that holds galaxies together, exerting a strong gravitational pull on surrounding stars, dust, and other material, causing them to orbit slowly around the black hole. However, if these materials are too close to the edge of the black hole, the so-called event horizon, they will be swallowed by the black hole and will never be able to escape.

Scientists have been observing the black hole of Marcarian 817 because it sometimes exhibits some strange behavior. Instead of swallowing the surrounding gas and dust steadily, the black hole will have some sudden eruptions, throwing the matter out at an extremely high speed, forming a cosmic wind. These cosmic winds can have a huge impact on galaxies, such as hindering the formation of new stars or even changing the shape of galaxies. But scientists have never seen a black hole like Markarian 817, whose cosmic winds last for hundreds of days and are several times faster than the speed of light. It's like a black hole throwing a tantrum and throwing out everything it doesn't like.

How did scientists discover this black hole storm? They use space telescopes that can detect different wavelengths of light, such as X-rays, ultraviolet rays, and gamma rays. This light is emitted by the hot material surrounding the black hole and can reflect the activity of the black hole. One such space telescope is called the Swift Observatory, a NASA project that can quickly observe unexpected events in the universe, such as supernova explosions or gamma-ray bursts. When scientists used the Swift Observatory to observe Markarian 817, they found that its X-ray light was significantly reduced, which means that the black hole's activity has changed. So they decided to take a closer look with another space telescope called XMM-Newton, a mission of the European Space Agency with its X-ray detectors that are very sensitive and can study complex celestial phenomena such as black holes, neutron stars and galaxy clusters.

When the storm of the black hole subsided, scientists saw its consequences. Most of the material around the black hole has been removed, creating an empty region in the galaxy that is about 3,000 light-years in diameter. In this region, few new stars are born because the cosmic winds blow away all the gas and dust needed for star formation. It's like a black hole has carved a no-go zone in its galaxy and doesn't let anything in. This phenomenon surprised scientists, who did not expect that black holes could have such an impact. Elias Carmon, an astronomer at the University of Rometre in Italy and co-author of the study, said in a statement: "This observation suggests that black holes may be reshaping their host galaxy far beyond imagination. ”

This discovery also provides new clues for us to understand the evolution of galaxies. Scientists believe that black holes and galaxies are closely linked, and their mass, shape, and brightness all have certain rules. The activity of black holes affects not only their own growth, but also the formation and evolution of galaxies around them, and the cosmic wind of black holes is an important feedback mechanism.

The storm of the black hole of Marcarian 817 not only gave us a glimpse into the wonders of a distant galaxy, but also gave us a new understanding of our own galaxy. Our galaxy also has a supermassive black hole called Sagittarius A*, which is about 4 million times more massive than the Sun. It is located in the center of the Milky Way, about 260,000 light years. Sagittarius A* is currently a relatively quiet black hole, it rarely erupts, and there are no strong cosmic winds. However, scientists have discovered that the region of galaxies around Sagittarius A* also has an empty region, about 500 light-years in diameter. Within this region, the density of stars is 10 times lower than in the surrounding area, and there are almost no new stars forming. This has left scientists wondering why a quiet black hole would have such an effect.

The storm of the black hole of Marcarian 817 has given scientists a possible answer. Perhaps, Sagittarius A* has had similar storms in the past, and its cosmic winds have also cleared the material around it, forming an empty area. It's just that these storms happened a long time ago, and we don't see any traces of them now. Scientists estimate that the last storm in Sagittarius A* may have occurred 4 million years ago, before humans appeared on Earth. If this assumption is true, then we can say that the storm of the black hole of Markarian 817 is a living microcosm of our galaxy's history, and it gives us a glimpse of what our own black hole once did.

This study also demonstrates the important role of the XMM-Newton as a space telescope. XMM-Newton is one of the most advanced X-ray detectors available, and it can observe some celestial phenomena that other telescopes can't see, such as the cosmic wind of a black hole. In a statement, XMM-Newton's project scientist Norbert Chartres said: "This underscores the importance of the XMM-Newton mission for the future. No other mission can combine its high sensitivity with the ability to observe for long periods of time, without interruption. ”

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