Astronomers have discovered a distant quasar — or active nucleus of a galaxy — that’s powered by a feeding supermassive black hole blasting out winds at record-breaking speeds of 30% the speed of light, around 201 million miles (323 million kilometers) per hour. This is the fastest black hole wind seen specifically in ultraviolet wavelengths.
The black hole-powered quasar, known as J2318, has an incredible mass of 1.7 billion times that of the sun and is located around 3 billion light-years away. While that is a pretty typical mass for a supermassive black hole, the speed of these winds is anything but typical, according to team member and York University researcher Patrick Hall.
“In terms of its speed, this quasar’s wind could be called a category 79 hurricane,” team leader and York University researcher Lucas Seaton said in a statement. “Every category of hurricane is about 20% faster than the category below it. Calling it category 79 gives an idea of just how fast it is, but of course this wind is unlike anything on Earth.”
All large galaxies are thought to host a supermassive black hole at their hearts with masses of millions, or even billions, of times that of the sun, but not all of these cosmic titans power quasars or emit such incredibly powerful winds. Quasars occur when these central supermassive black holes are surrounded by vast amounts of gas and dust called accretion disks. These disks gradually feed the black holes.
Black hole winds vs. Earth winds
As you might imagine, masses of millions or billions of times that of the sun generate incredible gravitational forces, and this means accretion disks can have powerful tidal forces of their own that create friction and cause them to glow brightly across the electromagnetic spectrum. This radiation also pushes matter away from accretion disks in the form of intense black hole “winds.”
“In quasars, we often see winds of gas pushed away from the black hole by the light of the quasar,” Seaton said. “The wind in J2318 can be seen at ultraviolet wavelengths at velocities up to 30% the speed of light. Even faster winds can be seen at X-ray wavelengths, but J2318 is the fastest ever discovered at ultraviolet wavelengths.”
The fact that black hole winds are radiation-driven, pushed by particles of light called photons bouncing off atoms (and not caused by air pressure) is what makes these cosmic gales so different from Earth’s atmospheric winds.
“Quasars put out so many photons that those tiny pushes add up to extreme velocities,” Seaton said. “The problem is, the photons can also remove all the electrons from the atoms, making them invisible. How to push the gas to the speeds we see while keeping the carbon and silicon ions we see intact … it’s quite a puzzle!”
To tackle this puzzle, the team turned to data observations made by the SDSS-IV Time-Domain Spectroscopic Survey and the SDSS-V Black Hole Mapper as part of the wider Sloan Digital Sky Survey (SDSS).
“Just as a rainbow spreads the sun’s light into different wavelengths, colours, the SDSS spreads out the light from certain stars, galaxies, and quasars into what we call their spectra,” Seaton said. “From those spectra, with practice, students learn to spot unusual quasars.”
These detailed spectra from J2318 revealed the high-speed winds of this quasar in ultraviolet light. The study of black hole winds like this one is important for understanding how galaxies evolve. That is because these winds are how supermassive black holes exchange energy with their galactic homes. In particular, this energy could push away gas and dust that serves as the raw material for star formation, thus quenching star birth in galaxies.
“These extreme outflows carry incredible amounts of energy that can affect the galaxies around them. They serve as a sort of missing link: the elusive feedback between the active central region of a galaxy and the rest of the galaxy,” Paola Rodríguez Hidalgo, associate professor at the University of Washington at Bothell, said in the statement. “While this process has been included in simulations of galaxy formation for decades, a lot more work needs to be done to understand it from observations and make sure the simulations handle it correctly.”
The team and other astronomers will continue to hunt for high-speed black hole winds in ultraviolet radiation, but aren’t confident they will find any as fast as the one from J2318.”It won’t be easy to find a faster ultraviolet outflow than that of J2318, but we are continuing this search from the nearby universe to the most distant reaches of the universe that we can see,” Flores concluded.
The team’s research was published on Thursday (June 4) in The Astrophysical Journal.