The giant X-ray "chimneys" are mouths for the huge energies produced in the center of the Milky Way

Today, an international team of astronomers has discovered two escape channels called "galactic center chimneys" – that seem to move the material and energy away from cosmic fireworks. located in the center of the Milky Way, about 28 000 light-years from Earth.

Mark Morris, professor of astronomy and astrophysics at UCLA, contributed to the research, which will be published on March 21 in the newspaper Nature.

"We hypothesize that these chimneys are mouths for all the energy released at the center of the galaxy," Morris said.

All galaxies are giant factories forming stars, but their productivity can vary greatly – from one galaxy to another and even during the life of each galaxy. One of the mechanisms to reduce the rate of production of stars is the fountain of matter and energy fanned by the very heavy black hole that is hiding in the center of the galaxy.

"Star formation determines the character of a galaxy," Morris said. "And that's something we hold dear because the stars produce the heavy elements from which planets and life are made."

To better understand what's happening with this energy release, Morris and his colleagues have been directing the European Space Agency's XMM-Newton satellite, which detects cosmic X-rays, towards the center of the Milky Way. Since X-rays are emitted by extremely hot gases, they are particularly useful for mapping energy environments in space.

In the images they collected from 2016 to 2018 and in 2012, the researchers found two X-ray plumes – the galactic center chimneys – that extend in opposite directions from the central center of the Galaxy. Each plume originates approximately 160 light years from the supermassive black hole and extends over 500 light-years.

The chimneys are connected to two gigantic structures known as Fermi bubbles, cavities dug in the gas that surrounds the galaxy. The bubbles, which are filled with high-speed particles, straddle the center of the galaxy and stretch for 25,000 light-years in both directions. Some astronomers suspect the Fermi Bubbles to be massive eruptions relics of the supermassive black hole, while others believe that the bubbles are destroyed by hordes of nascent stars. In both cases, chimneys could be the ducts through which high-speed particles arrive.

Understanding how energy moves from the center of a galaxy to its outer limits could help to understand why some galaxies are overflowing with stellar formations while others are dormant.

"In extreme cases, this source of energy can either trigger or stop the formation of stars in the galaxy," Morris said.

Our galaxy is not so extreme – other galaxies have fountains fed by central black holes weighing a thousand times more than ours – but the center of the Milky Way offers a close glimpse of what might happen in more energetic galaxies.

"We know that the flows and winds of matter and energy emanating from a galaxy are essential for sculpting and changing the shape of this galaxy over time, and play a key role in how galaxies and other structures are forming and evolving in the cosmos, "said lead author Gabriele Ponti of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany. "Fortunately, our galaxy provides us with a nearby laboratory to explore this issue in detail and explore how materials flow into the space around us."

Morris said the centers of the nearest galaxies are hundreds, even thousands of times farther away than ours. "The amount of energy coming out of the center of our galaxy is limited, but it's a very good example of a galactic center that we can observe and try to understand," he said.

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More information:
An X-ray chimney extending hundreds of parsecs above and below the galactic center, Nature (2019). DOI: 10.1038 / s41586-019-1009-6, https://www.nature.com/articles/s41586-019-1009-6