Supermassive black holes can fuel their own growth by cooling and recycling gas, creating a continuous cycle of feeding and outbursts.
- The central regions of galaxy clusters host the universe’s largest galaxies, each containing a supermassive black hole.
- Black holes release powerful jets that cause surrounding hot gas to cool, forming thin filaments of warm gas.
- Some of this warm gas eventually falls back into the black hole, fueling another outburst and continuing the cycle.
- Researchers used data from NASA’s Chandra X-ray Observatory, combined with optical observations, to study this process.
Black Holes Can Create Their Own Meals
Astronomers have made a key discovery showing that the universe’s largest black holes can help sustain their own growth. Using data from NASA’s Chandra X-ray Observatory and the Very Large Telescope (VLT), researchers found new evidence that black hole outbursts cool surrounding gas, making it easier for the black holes to draw in more material.
The study focused on seven galaxy clusters, which contain some of the most massive galaxies in the universe. At the heart of these galaxies are supermassive black holes, with masses ranging from millions to tens of billions of times that of the Sun. These black holes power jets that shoot out vast amounts of energy, a process fueled by the gas they consume.
Two of the galaxy clusters studied, Perseus and Centaurus, are featured in these images. The Chandra X-ray data, shown in blue, highlights hot gas filaments, while observations from the VLT, an optical telescope in Chile, reveal cooler filaments in red. These structures offer crucial clues about how black holes interact with their environment.
How Black Hole Outbursts Cool Gas
The results support a model where outbursts from the black holes trigger hot gas to cool and form narrow filaments of warm gas. Turbulence in the gas also plays an important role in this triggering process.
According to this model, some of the warm gas in these filaments should then flow into the centers of the galaxies to feed the black holes, causing an outburst. The outburst causes more gas to cool and feed the black holes, leading to further outbursts.
Astronomers Discover a Critical Relationship
This model predicts there will be a relationship between the brightness of filaments of hot and warm gas in the centers of galaxy clusters. More specifically, in regions where the hot gas is brighter, the warm gas should also be brighter. The team of astronomers has, for the first time, discovered such a relationship, giving critical support for the model.
This result also provides new understanding of these gas-filled filaments, which are important not just for feeding black holes but also for causing new stars to form. This advance was made possible by an innovative technique that isolates the hot filaments in the Chandra X-ray data from other structures, including large cavities in the hot gas created by the black hole’s jets.
An Unexpected Cosmic Connection
The newly found relationship for these filaments shows remarkable similarity to the one found in the tails of jellyfish galaxies, which have had gas stripped away from them as they travel through surrounding gas, forming long tails. This similarity reveals an unexpected cosmic connection between the two objects and implies a similar process is occurring in these objects.
This work was led by Valeria Olivares from the University of Santiago de Chile, and was published on January 27 in Nature Astronomy.
Reference: “An Hα–X-ray surface-brightness correlation for filaments in cooling-flow clusters” by Valeria Olivares, Adrien Picquenot, Yuanyuan Su, Massimo Gaspari, Marie-Lou Gendron-Marsolais, Fiorella L. Polles and Paul Nulsen, 27 January 2025, Nature Astronomy.
DOI: 10.1038/s41550-024-02473-8
The study brought together experts in optical and X-ray observations and simulations from the United States, Chile, Australia, Canada, and Italy. Researchers used the MUSE (Multi Unit Spectroscopic Explorer) instrument on the VLT, which provides detailed 3D views of the universe.
NASA’s Marshall Space Flight Center in Huntsville, Alabama, oversees the Chandra program, while the Smithsonian Astrophysical Observatory’s Chandra X-ray Center manages science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
