Scientists just found five of the most distant and most extreme gamma-ray blazars ever detected. Blazars are galaxies that blast particle jets at the speed of light in opposite directions. Researchers presented their findings Monday at the American Physical Society meeting in Washington, D.C., and they have submitted a paper to The Astrophysical Journal Letters journal.
Blazars have really intense, high-energy emissions that scientists believe are powered by supersized black holes. As matter falls towards a black hole, it is heated, ripped apart violently and corralled into a disk before it plunges into the black hole’s abyss. “Black holes are not picky eaters,” Roopesh Ojha, an astronomer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland who was part of the research team, tells Inverse.
These black holes that power blazars are way bigger and brighter than we can even imagine. They’re about a million or more times the sun’s mass. In fact, two of the blazars found have black holes that are at least a billion times the mass of the sun.
“Blazars are the most powerful objects in the Universe,” Vaidehi Paliya of Clemson University, who helped lead the research team, tells Inverse. “In fact, this is the reason that we are able to detect them, though they are so far from us. The power released by these monsters in each second is larger than the total energy output of the Sun in its entire lifetime.”
And they’re super bright in all forms of light, including gamma rays when a jet points directly towards us. Blazars emit two trillion times the energy output of the sun, making them some of the most luminous objects in the universe.
Although they’re bright, light can only travel at, well, the speed of light. The light from these blazars started traveling towards us when the universe was 1.4 billion years old — meaning they’re located 1.4 billion light-years away. They were formed when the universe was just 10 percent its current age.
“When we observe a distant object we are seeing it the way it was when the light left that object — looking at the sky is really like going back in time,” Ojha says.
Researchers used NASA’s Fermi Gamma-ray Space Telescope, and blazars make up about half of the gamma-ray sources detected by this telescope. For example, in 2015, the Fermi found a blazar that’s so far away, the light took half the age of the universe to reach us (it’s 7.6 billion light years away). Going forward, the team will continue observing these five blazars in different kinds of light to better understand the physics behind them and continue looking for blazars located at even larger distances — probing the universe’s beginnings.
Before the Fermi detected these five blazars, the most distant blazar detected by Fermi started emitting light when the universe was 2.1 billion years old.
“Blazars hold the key to understand the evolution of the universe,” Paliya says. “The universe as we know today was very different at its beginning. A study of these distant blazars enables us to understand some of the most fundamental questions such as how the universe evolved.”
