After decades of research, scientists are making significant progress in the mystery surrounding black holes in our galaxy

Every large galaxy contains… Supermassive black hole At their centre, each emits powerful winds of hot gas from the event horizon. Our galaxy He should Don’t be an exception. However, for the past 50 years or so, astronomers have been searching for winds coming from the black hole at the center of the Milky Way, and in all this time, they have found nothing. Not even a gentle breeze.

yet. In a preliminary study, a team of scientists has detailed the strongest evidence yet found for winds flowing from a black hole in the Milky Way. Sagittarius A*. The results of the hack were posted on a preprint server arXiv In September, he described a large, cone-shaped region around a black hole where cold gas appears to have been blown away.

“If this is true, it will be a very exciting discovery with some very broad implications for the center of our galaxy,” said Leah Hankla, a postdoctoral astrophysicist at the University of Maryland who was not involved in the study. sciences. While they suggest that the missing gas is indirect evidence of black hole winds, the results represent a major step forward in resolving the issue.

Searching for the winds of Sagittarius A*

Contrary to popular belief, black holes don’t just absorb everything that approaches them. When gas spirals into the disk of matter surrounding a supermassive black hole, it heats up. Through a complex combination of magnetic, radiation and thermal effects, some of this gas is released in the form of winds or high-speed plasma jets.

Supermassive black hole winds are so powerful, they shape how the host galaxy evolves. Astronomers know, for example, that winds help keep intergalactic gas hot and inhibit star formation, limiting galaxy growth too large. Understanding how these dynamics occurred at the center of the Milky Way is key to understanding how they evolved over time, and tracing our origin story.

Many astronomers have searched for Sagittarius A*’s winds, but previous telescope observations have yielded conflicting results, largely because of the difficulty of looking through all the gas, dust, and stars covering the galactic core.

However, in this new study, a new telescope in Chile has risen to the occasion. The Atacama Large Millimeter/submillimeter Array (ALMA) is the world’s most powerful radio telescope. Compared to optical telescopes, they are exceptionally good at penetrating dust clouds.

How did they do it?

Astrophysicist Lena Morchikova and astronomer Mark Gorsky, both of Northwestern University, have combined nearly five years of ALMA observations with state-of-the-art data processing techniques to produce an unprecedented detailed map of the cold molecular gas around Sagittarius A*.

This map revealed a cone-shaped gap in the cold gas cloud. When the researchers superimposed their map on X-ray data collected by NASA’s Chandra X-ray Observatory, it matched the cone shape exactly. The alignment suggests that hot plasma winds from Sagittarius A* are blowing cold gas away, emitting X-rays in the process.

These results bring scientists closer than ever to solving the mystery of Sagittarius A*’s missing winds, but that is not the case completely closed. Direct evidence, such as measuring the speed of particle flow from a black hole, is still elusive. But while the answer to that question is getting closer, astronomers are still doing their best to understand the mysterious heart of our galaxy.