Dark matter halo: New discovery? It may help humans understand the evolution of the universe!

"Follow this arduous journey to reach the stars" and get closer to the mysterious dark matter halo.

Measurements of the mysterious matter surrounding these quasar galaxies could have profound implications for our understanding of how the universe evolved.

Illustration of a dark matter halo.

(Image credit: Artist's rendering by Christopher Dessert, Nicholas L. Rode, Benjamin R. Safdie, and Zosia Rostomian (Berkeley Lab) based on data from the Fermi Gamma-ray Space Telescope).

A team of astronomers has for the first time "weighed" the dark matter halos surrounding supermassive black holes active in the bright centers of ancient galaxies.

Measurements of the mysterious forms of matter surrounding these quasar galaxies could have profound implications for our understanding of how the universe evolved.

These black hole-powered "hearts" (or quasars) often outshine all the stars in their surrounding galaxies combined. These super-bright central regions "burn" when supermassive black holes, billions of times more massive than our sun, begin to devour surrounding matter.

According to new research, scientists believe that the dark matter halos around these active galaxies help transport matter to the central black holes, providing a cosmic delivery service and helping to feed Titan. The new study shows that such a feeding mechanism does exist around hundreds of ancient quasars, and that this process has continued throughout the history of the universe.

"For the first time, we have measured the mass of a typical dark matter halo surrounding an active black hole in the universe about 13 billion years ago," team leader Nobushige Kashiwagawa, a professor in the Department of Astronomy at the University of Tokyo, said in a statement. "We found that the mass of the dark matter halo around quasars is very stable, about 10 trillion times the mass of the sun. We have measured the mass of the younger dark matter halo around quasars, and these measurements are surprisingly similar to our measurements of older quasars."

"This is interesting because it suggests that there is a unique dark matter halo mass that seems to be able to activate quasars, both billions of years ago and now."

Since the supermassive black hole at the center of a galaxy can strongly affect the formation of stars and the growth of the entire galaxy, this unexpected discovery by Nobuyuki Kashiwa's team may have a profound impact on scientists' study of how galaxies grew in the early universe and how the universe evolves.

Weighing the dark matter content of ancient galaxies

The image shows the mass of the dark matter halo surrounding quasars at the centers of ancient active galaxies.

The nature of dark matter is an urgent question for science. Although it makes up about 85 percent of all matter in the universe, dark matter does not interact with light, so we cannot see it.

From the gravitational effects of dark matter, astronomers can infer not only the existence of dark matter, but also the effect of this effect on standard everyday matter, including stars, cosmic dust and gas clouds, planets in galaxies, and the light passing through these galaxies. Eventually, the elusiveness of gravitational effects led scientists to realize that most galaxies must be surrounded by some kind of dark matter halo. If there was only the gravity of visible matter within the galaxies, then the galaxies would not be able to hold together while rotating at high speeds.

But even with these improved dark matter inference techniques, it’s still difficult to measure the mass of this invisible stuff in the halos around nearby galaxies. And measuring dark matter around more distant galaxies—that is, the dark matter of early galaxies—is even more challenging because the light these galaxies emit is so faint.

However, Kashiwa is not intimidated by these challenges. He and his team hope to further understand how black holes grew in the early universe. Thanks to the brightness of hundreds of the largest and most powerful supermassive black holes, which fuel quasars, researchers were able to measure the dark matter halos around ancient galaxies for the first time.

The light from these ancient quasars traveled through the universe for 13 billion years before being captured by telescopes. During this epic cosmic journey, the light lost energy and stretched its wavelength, moving down from the red end of the visible light spectrum to infrared wavelengths—a process astronomers call “redshift.”

We've never seen dark matter and dark energy, so why do we think they exist?

Researchers are digging deep underground in hopes of eventually observing dark matter.

Massive galaxies without dark matter are a cosmic puzzle.

In 2016, Kashiwa and his team began collecting infrared data from a series of astronomical observations using a variety of instruments, primarily the Subaru Telescope atop Maunakea in Hawaii.

This allowed them to see how the light from these quasars was altered by the gravity of dark matter. Dark matter, like all matter with mass, warps the fabric of space, causing the path of light to bend — a process astronomers call gravitational lensing. Measuring the degree of bending and comparing it to what should be produced by the mass of common matter like gas, dust and stars in a galaxy reveals the mass of the hidden dark matter.

"The new generation of Subaru Telescopes can see farther than ever before, but we can also expand international observation projects to learn more," Kashiwa added. The Vera Rubin Observatory in Washington and even the Euclid satellite launched by the European Union this year will explore a wider area of ​​the sky and discover more dark matter halos around quasars.

"We can study the relationship between galaxies and supermassive black holes more comprehensively. This may help us understand how black holes form and grow."

BY: Robert Lea

FY: Qin Ban Liang

If there is any infringement of related content, please contact the author to delete it after the work is published.

Please obtain authorization for reprinting, and pay attention to maintaining integrity and indicating the source