Scientists discover black hole winds shaping surrounding galaxies

An artist's impression of a quasar wind (in light blue) being launched off of the accretion disk (red-orange) around a supermassive black hole. Credit: NASA/CXC/M. Weiss, Catherine Grier and the SDSS collaboration.

Researchers have discovered that powerful winds from supermassive black holes can significantly influence the development of surrounding galaxies.

A team led by University of Wisconsin–Madison astronomy professor Catherine Grier and recent graduate Robert Wheatley found that gas clouds in a distant galaxy are being pushed out at speeds exceeding 10,000 miles per second by radiation blasts from a central black hole.

This discovery sheds light on how active black holes can shape their galaxies by either promoting or hindering the formation of new stars.

The research focused on a quasar, a highly bright and turbulent type of black hole, located billions of light years away in the constellation Boötes.

Using data collected over eight years, the team studied the quasar known as SBS 1408+544. Their findings were presented at the 244th meeting of the American Astronomical Society in Madison.

Quasars are supermassive black holes surrounded by disks of matter being pulled in by the black hole’s immense gravitational force.

This process creates a lot of friction, heating up the disk and making it extremely bright. Grier explains, “These quasars are really luminous, and their emission covers almost all of the electromagnetic spectrum.”

The bright light from quasars makes them visible even from as far as 13 billion light years away, making them useful tools for astronomers studying the early universe.

The researchers used observations from the Sloan Digital Sky Survey’s Black Hole Mapper Reverberation Mapping Project to track the winds composed of gaseous carbon.

They identified the movement of these winds by observing light from the quasar that was being absorbed by the gas. Instead of being absorbed at the expected spot in the spectrum, the shadow of the gas shifted further with each new observation of SBS 1408+544.

Wheatley explains, “That shift tells us the gas is moving fast, and faster all the time. The wind is accelerating because it’s being pushed by radiation blasted off the accretion disk.”

Although scientists, including Grier, had previously suggested the presence of accelerating winds from black hole accretion disks, this study is the first to be supported by extensive data from over 130 observations made over nearly a decade.

This long-term data allowed the team to confirm the increase in velocity with high confidence.

These winds are of particular interest because they may influence the evolution of the galaxies surrounding supermassive black holes.

“If they’re energetic enough, the winds may travel all the way out into the host galaxy, where they could have a significant impact,” says Wheatley. Depending on the circumstances, the winds could either compress gas to speed up star formation or blow away the gas, preventing new stars from forming.

Grier adds, “Supermassive black holes are big, but they’re really tiny compared to their galaxies. That doesn’t mean they can’t ‘talk’ to each other, and this is a way for one to talk to the other that we will have to account for when we model the effects of these kinds of black holes.”

The study of SBS 1408+544, published in The Astrophysical Journal, included collaborators from York University, Pennsylvania State University, University of Arizona, and others.

Source: University of Wisconsin-Madison.