Researchers have directly observed a phenomenon in the core of another galaxy that suddenly increased in brightness, seemingly due to a supermassive black hole awakening and beginning to consume surrounding material.
At the center of the Milky Way lies a supermassive black hole named Sagittarius A* (Sgr A*), which has a mass four million times that of the Sun, but is affectionately nicknamed the “gentle giant” by scientists due to its quiet nature.
However, one day, this dormant “Sagittarius” could turn into a monster.
On June 18, researchers announced that they had directly observed a phenomenon in the core of another galaxy increasing in brightness, apparently because a supermassive black hole awakened from its dormant state and began to consume nearby material. This is the first time this awakening process has been seen as it unfolds.
Supermassive black hole named Sagittarius A*. (Source: Reuters).
Ground-based and orbital telescopes have been used to monitor events occurring in the core of the galaxy SDSS1335+0728, located approximately 360 million light-years away from Earth in the Virgo constellation. A light-year is the distance that light travels in one year, equivalent to about 9.5 trillion kilometers.
Black holes are objects with extremely high density and gravitational pull so strong that even light cannot escape. They vary in size, from masses equivalent to a single star to “monster” black holes that exist at the core of many galaxies with masses millions or even billions of times that of a star. The supermassive black hole in the galaxy SDSS1335+0728 has a mass approximately one million times that of the Sun.
The environment surrounding a supermassive black hole can be incredibly chaotic as it tears apart stars and consumes any material within its gravitational reach.
Researchers noted that it appears a rotating disk of diffused material has formed around the supermassive black hole of SDSS1335+0728, with some material being consumed.
Such a disk—known as an accretion disk—emits energy at very high temperatures, sometimes brighter than an entire galaxy. A glowing region concentrated in one place, powered by the supermassive black hole at the center of a galaxy, is referred to as an “active galactic nucleus.”
“These nuclei are characterized by emitting large amounts of energy across various wavelengths, from radio waves to gamma rays. They are considered some of the brightest objects in the universe,” said astronomer Paula Sanchez Saez from the Southern European Observatory in Germany, the lead author of the study published in the journal Astronomy & Astrophysics.
Studying active galactic nuclei plays a crucial role in understanding the evolution of galaxies and the physical characteristics of supermassive black holes.
The galaxy SDSS1335+0728, with a diameter of approximately 52,000 light-years and a mass equivalent to about 10 billion solar-mass stars, has been observed for decades before sudden changes were detected in 2019. Brightness in the center of the galaxy has increased in observations since then.
According to astronomer and co-author of the study Lorena Hernandez Garcia from Valparaiso University in Chile, supermassive black holes sometimes emit giant jets of high-energy particles into space, but no such jets were detected in this case.
So, what could have triggered this supermassive black hole?
“At present, we do not know,” Sanchez said. “It could be a natural process of the galaxy,” Hernandez added.
“We know that a galaxy goes through different active and inactive phases throughout its lifetime. Something could happen to trigger a galaxy, such as a star falling into the black hole.”
If the observed phenomenon is not the beginning of an active galactic nucleus, it could represent an unprecedented astronomical physical phenomenon.
Sagittarius A*, or Sgr A*, is located approximately 26,000 light-years from Earth. Could it also suddenly “wake up”?
“A similar process could eventually happen with Sgr A*, which is currently dormant. But right now, we are not in danger, and perhaps if it activates, we won’t even notice because we are so far from the center,” Hernandez commented.
