According tomedia reports, black holes are often very “bright” in the sky. This is because they are surrounded by a glowing ring of dust and gas, called the “corona” of black holes. Now, astronomers have been disbelief to see the sudden disappearance of a black hole’s corona — but strangely it resurfaced a few months later.
The black hole is a supermassive “monster” located at the center of a galaxy about 100 million light-years away. And it’s particularly “greedy”, a class of things called active galactic nuclei (AGnNs), that glow as they constantly devour matter that enters their bodies.
The story began in March 2018, when an ordinary AGN, codenamed 1ES 1927-654, exploded 40 times brighter than usual. The flash was discovered by the All-Day Auto-Supernova Discovery Project (ASSASN), which reminds astronomers to point other telescopes at the object. When the scientists observed the AGN in X-ray, optical and ultraviolet light, they watched in amazement as the light gradually weakened and its brightness darkened to one-tenth of its original level until it could no longer be detected at all. Scientists have never seen such a burning burn happen so quickly.
“We expect that such large photometric changes should vary on the scale of thousands of years to millions of years,” said Erin Kara, co-author of the study. “But in this object, we see it become one-tenth of the original in a year, and even one percent in eight hours, which is completely unheard of, really incredible.”
But it’s not over yet. Within a few months, the light was rekindled, almost rekindling the original light, which had never been seen before. So what’s going on? Astronomers believe that as a source of light, the “corona” of black holes is severely damaged and may even be destroyed. This explains the subduction and regression of light, as the disk may later correct its position and be swallowed up again by the black hole.
Even so, what kind of disaster can cause such damage? One hypothesis put forward by the team is that a star is too close to be torn apart by a black hole. The initial flares may have been caused by the destruction of stars, and intense gravity could cause material from the corona to fall off into a black hole. Then, over time, more matter accumulates, eventually providing energy for AGN and making it brighter again.
“It seems to be the first time we’ve ever seen the corona disappear first, but then rebuild ourselves, and we’re looking at that in real time,” Kara said. “This will be important to understand how the corona of a black hole is first heated and powered.” The team continued to focus on the object.
The study was published in the Astrophysical Journal Of Letters.