Supermassive black holes lie in the centers of most galaxies, including our own Milky Way, and the weight of these black holes is so immense that they even eclipse the sun, with a mass that is millions or, in some cases, even billions of times greater than the sun. But what makes these supermassive black holes so very large? Astronomers believe they have finally learned just how these black holes are “fed.”
To reach their very weighty stature, supermassive black holes can swallow up anything from stars to gas. But as Phys.org reports, up until very recently, scientists were unsure as to how they grew so large so quickly, or how they were able to just suddenly “switch on,” with a growth period that lasts as long as it does.
However, a new study by scientists from Tel Aviv University may have solved this mystery once and for all. After scientists studied data extracted from the All Sky Automated Survey for Supernovae which took place in February 2017, what was believed to be either a “tidal disruption” event or a “star swallowing” event occurred, which has been called AT 2017bgt.
After observing this event, scientists noted that the aura of radiation surrounding the supermassive black hole they were studying was a whopping 50 percent brighter than it was during the last time it was witnessed, which was back in 2004.
Dr. Benny Trakhtenbrot and Dr. Iair Arcavi, from TAU’s Raymond & Beverly Sackler School of Physics and Astronomy, discovered that the event known as AT 2017bgt was really what they have referred to as a “feeding” event for supermassive black holes.
As Dr. Trakhtenbrot explained, “The sudden brightening of AT 2017bgt was reminiscent of a tidal disruption event. But we quickly realized that this time there was something unusual. The first clue was an additional component of light, which had never been seen in tidal disruption events.”
Dr. Arcavi further added that after observing AT 2017bgt, it was quickly apparent that this was a completely new phenomenon.
“We followed this event for more than a year with telescopes on Earth and in space, and what we saw did not match anything we had seen before.”
Tel Aviv University’s Professor Hagai Netzer noted that while what they were witnessing had been technically predicted in the past, it had never actually been seen before and proven.
“We had predicted back in the 1980s that a black hole swallowing gas from its surroundings could produce the elements of light seen here. This new result is the first time the process was seen in practice.”
The Tel Aviv University research team responsible for the latest discovery also learned about two additional supermassive black holes which appeared to be “switched on” and that also shared similar emission traits with AT 2017bgt. Dr. Arcavi is hopeful that they will be able to discover and study even more of these special black holes to learn more about their sudden expansion and growth.
The new study which describes the frenzied “feeding” of supermassive black holes has been published in Nature Astronomy.