Ravenous, strange and bewitching, supermassive black holes the mysterious hearts of perhaps all the great galaxies in the observable Universe are believed to lurk, including our own Milky Way. The resident dark heart of our galaxy is called Sagittarius A * – Sgr A *, for short (pronounced saj-a-star), and now he’s dormant, but still manages to wake up from his sleep every now and then to dine on an unfortunate star or gas cloud that has gotten too close to his gravitational embrace. Sgr A *Despite its currently calm nature, it still has enough “life” left to surprise astronomers with a sudden and dramatic episode of turbulent activity. In October 2019, a team of astronomers announced that they had found evidence of a recent cataclysmic flare that exploded so far from the Milky Way that its destructive influence was felt 200,000 light-years from its origins.
This huge expanding beam of energy erupted near Sgr A * just a “mere” 3.5 million years ago, which is just the blink of an eye in cosmic time. The flare shot a cone-shaped blast of radiation through both poles of our Galaxy, which then hurtled screaming into deep space.
This new finding is based on research by a team of scientists led by Dr. Joss Bland-Hawthorn from Australia. ARC Center of Excellence for All the astrophysics of the sky in 3 dimensions (ARSTRO 3D). His work is published in The Astrophysical Journal.
The bewitching heart of our Milky Way
Sgr A * it is a bright and compact astronomical radio source. It is located in the heart of our great spiral galaxy, near the edge of the constellations. Sagittarius Y Scorpius. As supermassive black holes advance, Sgr A * it is relatively light in weight. Similar dark hearts that inhabit other galaxies glow millions to billions of times brighter than our Sun. Sgr A * sports “only” millions of solar masses.
Observations of many stars circling Sgr A * have been used to provide important evidence for the presence of, as well as to provide data on, our Milky Way supermassive black hole. These observations have led some astronomers to conclude that Sgr A * it is a black hole without a shadow of a doubt.
The crushed remains of what were once stars, as well as the unfortunate and disrupted gas clouds, create the debris that eventually falls into the waiting jaws of a supermassive gravitational beast like Sgr A *. This terrible feast of swirling material creates a massive disk that surrounds the black hole. The disk itself, called accretion disk, it gets hotter and hotter as time goes by, particularly when it is pushed into the strange vortex near the dreaded point of no return, called the event horizon. Nothing can return to the outside once it has entered this point. Not even light can return once it has been ingested. Tea event horizon is situated in the innermost region of the bright accretion disk.
Supermassive black holesalong with its dazzling surroundings accretion discs, it can be as big as our Solar Systemat least. These mysterious entities are described by their greedy appetites, large masses, and messy table manners. When Sgr A * it was a young black hole, billions of years ago, it shot the fantastic light like a fiery, dazzling youth quasar in the ancient Universe. However, he has grown quiet in his old age, with only a shadow of the appetite he once had when he was in his brand new youth. Quasars illuminated the ancient Universe, but as Sgr A * many of them have also lost their shine in old age.
All black holes are dense and compact regions of space. Sgr A * the compressed mass of about 4.5 million suns looks like, and this large mass is compressed into a relatively small area of space.
In an article published on October 31, 2018, astronomers announced their discovery of conclusive evidence that Sgr A * it is a black hole. Using the GRAVITY interferometer and a quartet of telescopes from the Very Large Telescope (VLT) To form a virtual telescope 130 meters in diameter, the scientists detected groups of gas traveling at approximately 30% of the speed of light. Emission of very energetic electrons very close to Sgr A * it was visible as a trio of bright flares. The flares matched precisely with theoretical predictions of hot spots circling near a black hole roughly four million times the solar mass. The flares are believed to originate from magnetic interactions in extremely hot gas circulating near our galaxy’s resident dark heart.
What has been seen, so far, of Sgr A *, it is not the black hole itself. However, observations are consistent only if there really is a black hole lurking nearby. Sgr A *. In the case of such a black hole, the observed radio and infrared energy emanates from gas and dust that is heated to millions of degrees as it falls to its doom in the jaws of the black hole. But the dark-hearted beast itself is believed to emit only Hawking radiation it was at a negligible temperature.
Sgr A * it is invisible to the eyes of observers. Like all others of its kind, it does not send energy into space and is completely dark. Our galaxy’s ancient and quiet resident supermassive black hole shows little of the voracious appetite of its youth, when it was still in its bright quasar practices. In fact, at least in the case of Sgr A *, it’s been a long time between dinners. It is believed that he feasted on his last great buffet some six million years ago, when he dined on an unfortunate large cloud of spoiled gas. Subsequently, the neglected black hole, its hunger now quenched, sent a huge bubble of gas into interstellar space that was equivalent to millions of solar masses. This gas bubble now bounces both below and above Sgr A *. These bubbles after dinner are called Fermi Bubbles, and were first discovered by NASA Fermi Gamma Ray Space Telescope in 2010.
Black holes are indisputably strange inhabitants of the cosmic zoo. Our Galaxy’s own resident beast is surrounded by a scintillating cluster of baby stars, some of which have had the misfortune to fall within a few million miles of where Sgr A * he was waiting terribly for his dinner to fall apart.
Not all black holes are from supermassive nice. In fact, there are black holes smaller than just stellar mass inhabiting the Cosmos. These much lighter black holes form when an especially massive star has finished burning its necessary supply of nuclear fusion fuel, and explodes into oblivion when its core collapses. This results in a Type II (core collapse) supernova explosion. There is also a probable population of intermediate-sized black holes weighing among the mass of black holes of only stellar mass and the supermassive variety. It has also been suggested that a population of hypothetical primordial black holes they were born at the birth of the Big Bang of the Universe almost 14 billion years ago. In fact, if enough mass is squashed into a small enough space, a black hole will invariably form.
Seyfert Flare
The violent flare that broke the heart of our galaxy is known as Seyfert Flare. Created two huge ionization cones that traversed our Milky Way, starting with a relatively small diameter near Sgr A *, and then they swelled enormously as they ran out of our Galaxy.
This particular Seyfert Flare He was so powerful that he ran into it Arroyo de Magallanes, which is a long gas trail that runs from the Big and Small Magellanic Clouds, which are two dwarf galaxies close to our own. Tea Arroyo de Magallanes it is situated at an average distance of 200,000 light years from our Milky Way.
The catastrophic explosion was so powerful, according to the Australian team of astronomers, that it could not have been caused by anything other than nuclear activity originating from our galaxy’s supermassive black hole.
“The flare must have been a bit like a beacon beam,” Dr. Bland-Hawthorne commented on October 2, 2019. ScienceinPublic press release. Dr. Bland-Hawthorne is also from the University of Sydney in Australia.
“Imagine the darkness, and then someone lights a beacon for a lighthouse for a short period of time,” he added.
Using data collected by the Hubble Space Telescope (HST), scientists determined that the huge explosion occurred just a little over three million years ago, a mere wink of an eye on cosmological timescales. In fact, in galactic terms, that’s surprisingly recent. On our own planet, at that time, the asteroid that was the final and fatal blow to the dinosaurs was 63 million years ago. The ancient ancestors of humanity already existed. He called the Australopithecines, these ancestors of human beings already roamed the African continent.
“This is a dramatic event that happened a few million years ago in the history of the Milky Way,” noted Dr. Lisa Kewley on October 2, 2019. ScienceinPublic press release. Dr. Kewley is Director of ASTRO 3D.
“A massive burst of energy and radiation hit the center and the surrounding material. This shows that the center of the Millky Way is a much more dynamic place than we had previously thought. It is fortunate that we are not residing there,” he said . additional.
The explosion, astronomers estimate, lasted just 300,000 years. This is an extremely short period in galactic terms.
In conducting the research, Dr. Bland-Hawthorne was joined by colleagues from the Australian National University and the University of Sydney and, in the US, the University of North Carolina (Chapel Hill), the University of Colorado (Boulder) and the Space Telescope Science Institute in Baltimore, Maryland.
The new article follows previous research, also conducted by Dr. Bland-Hawthorne, which was published in 2013. The previous work studied the evidence for a tremendous explosive event that originated in the center of our galaxy, and ruled out a nuclear explosion. as a trigger. . Instead, the earlier study tentatively linked the explosion to activity in Sgr A *.
“These results dramatically change our understanding of the Milky Way,” commented study co-author Dr. Magda Guglielmo of the University of Sydney, Australia.
“We always think of our galaxy as a dormant galaxy, with a not-so-bright center. These new results open the possibility of a complete reinterpretation of its evolution and nature. The flare event that occurred three million years ago was so powerful that it had consequences in the surroundings of our Galaxy. We are witnesses of the awakening of the sleeping beauty “, continued.
Recent research considers Sgr A * as the main suspect. However, the researchers acknowledge that there is still much work to be done. The way black holes evolve, influence and interact with galaxies, they conclude, “is an outstanding problem in astrophysics.”