Black Holes’ Unusual Behavior Shapes Galaxy Structure

The European Space Agency (ESA) has unveiled new findings on the behavior of black holes, revealing their unexpected role in galaxy formation. These black holes, typically considered cosmic devourers, have been observed propelling matter away from their cores at high speeds.

Side view of a galaxy with spiral arms of bright blue stars separated by dark bands of interstellar dust. The galaxy’s active centre is blasting out a strong wind of gas in all directions, shown as yellowish-white streaks. An inset zooms in on the centre, showing that the wind is coming from a swirling disc of gas, lit up in orange and yellow, which encircles a supermassive black hole. Credits: ESA (acknowledgement: work performed by ATG under contract to ESA) — This artist impression shows ultra-fast winds blasting out from the centre of galaxy
Markarian 817. Credits: ESA (acknowledgement: work performed by ATG under contract to ESA)

This ejection of material creates a void between the black hole and the surrounding galaxy, impeding the condensation of matter and thus the formation of new stars.

Markarian 817’s surprising winds

Previously, ultra-fast black hole winds were detected only in extremely bright accretion disks, at the brink of their matter-attracting capacity. However, ESA’s XMM-Newton telescope has now observed similar winds in a moderately active galaxy, Markarian 817.

This finding is significant as it demonstrates that even less active black holes can produce impactful winds, capable of altering their host galaxy’s structure. Elias Kammoun, an astronomer at Roma Tre University, Italy, notes:

“The fact that Markarian 817 produced these winds for about a year, while not being particularly active, suggests that black holes may reshape their host galaxies much more than previously thought.”

: Rings of brilliant blue stars encircle the bright, active core of this spiral galaxy. Called Markarian 817, it lies 430 million light-years away in the northern constellation of Draco. Credits: NASA, ESA and the Hubble SM4 ERO Team — Rings of brilliant blue stars encircle the bright, active core of this spiral galaxy. Called
Markarian 817, it lies 430 million light-years away in the northern constellation of Draco. Credits: NASA, ESA and the Hubble SM4 ERO Team

The silent X-Rays of a black hole

The anomalous observation of Markarian 817 initially made through NASA’s Swift observatory revealed an unusually low X-ray signal, initially suggesting a measurement error. However, further verification using ESA’s more sensitive XMM-Newton telescope uncovered the true cause: ultra-fast winds from the accretion disk were blocking part of the X-rays.

A detailed analysis of the X-ray data revealed that instead of emitting a single burst of gas, the center of Markarian 817 produced a gusty storm over its accretion disk. This wind, lasting several hundred days, comprised at least three distinct components, each moving at a significant fraction of the speed of light.

The X-Ray vision of XMM-Newton

This study was primarily enabled by the capabilities of ESA’s XMM-Newton. Launched on December 10, 1999, from the Centre Spatial Guyanais in Kourou, the XMM-Newton (X-ray Multi-Mirror Mission) is an advanced orbital observatory developed by the European Space Agency (ESA) for X-ray astronomy. It was designed to probe high-energy astrophysical phenomena.

An artist's impression of XMM-Newton Telescope. Credits: ESA/C. Carreau — *An artist’s impression of XMM-Newton Telescope. Credits: ESA/C. Carreau*

Equipped with three X-ray telescopes, each containing mirror modules nested in a concentric configuration to maximize the effective X-ray collection area, XMM-Newton stands as a premier engineering achievement.

The observatory includes the European Photon Imaging Camera (EPIC), which is sensitive to rapid changes in intensity, and high-resolution spectroscopy instruments that allow for the analysis of the chemical composition, temperature, and velocities of astrono mical sources. Originally envisioned with a 10-year operational lifespan, the XMM-Newton mission has far exceeded these expectations.

Black holes’ role in star formation and galaxy structure

The ESA’s XMM-Newton observations have unveiled a transformative aspect of black holes, demonstrating their ability to significantly influence galaxy evolution. By ejecting a portion of the accreting material back into space, these black holes limit their own growth and regulate the formation of new stars within their host galaxies.

This process creates a dynamic interplay between the accumulation and dispersion of matter, highlighting a complex feedback mechanism that shapes the co-evolution of black holes and galaxies. These findings offer profound insights into the intricate balance of forces governing galactic structure and evolution, marking a significant advancement in our understanding of cosmic phenomena.