Scientists have gained an unprecedented view into the turbulent environments surrounding supermassive black holes, revealing how these cosmic giants impact their surroundings. Data from the X-ray Imaging and Spectroscopy Mission (XRISM), launched in 2023, has allowed researchers to directly measure the kinetic energy of gas stirred by black holes in the Perseus and Virgo galaxy clusters.
Black Holes in the ‘Eye of a Storm’
The research, published in on , and reported by Universe Today on , demonstrates that supermassive black holes aren’t simply consuming matter, but actively injecting energy into the surrounding gas, creating what researchers describe as being “in the eye of their own storm.” This energy injection impacts the evolution of galaxies and the formation of stars within them.
The Perseus Cluster, the brightest X-ray source in the sky, served as a key focus for the XRISM observations. Astronomers had long suspected that the gas within galaxy clusters wasn’t static, but rather undergoing complex motions driven by both the growth of the cluster itself and the activity of the central black hole. However, directly measuring these gas motions proved challenging until the arrival of XRISM.
XRISM’s unique capability lies in its ability to precisely measure the slight shifts in the wavelengths of light emitted by elements within the hot gas. These shifts, known as the Doppler effect, reveal whether the gas is moving towards or away from Earth, and at what speed. The satellite can resolve detailed absorption features in X-ray binaries, mapping the motion and distribution of hot gas near black holes at previously unreachable levels of detail.
Mapping Gas Motions and Turbulence
Building on earlier observations from the X-ray astronomy satellite ASTRO-H, XRISM expanded the observational range to 800,000 light-years within the Perseus Cluster. This allowed scientists to create a detailed map of gas velocities. The data revealed a distinctive V-shaped pattern in the velocity of the gas. Near the supermassive black hole at the center of the cluster, the gas exhibits velocity variations of up to 200 kilometers per second – approximately 35% of the gas’s sound speed. Further out, the velocity drops to 80 kilometers per second before rising again to 200 kilometers per second.
This pattern, researchers explain, can be understood by drawing an analogy to terrestrial weather phenomena. Large-scale atmospheric flows, like those associated with hurricanes or typhoons, generate smaller-scale turbulence, such as swirling eddies and irregular air currents. Similarly, the large-scale growth of the galaxy cluster, driven by dark matter, creates a broad “storm” of gas motion. Superimposed on This represents a smaller, more intense “whirlwind” of turbulence caused by the activity of the central supermassive black hole.
The outer regions of the V-shaped pattern represent the gas motion driven by the cluster’s growth over billions of years, a testament to the ongoing process of accretion. The inner, more turbulent region is directly linked to the black hole’s activity. The black hole in the Perseus Cluster is estimated to be 200 times more massive than the supermassive black hole at the center of our own Milky Way galaxy.
Energy Injection and Star Formation
Supermassive black holes aren’t simply “vacuum cleaners” of space, but actively release energy into their surroundings through powerful jets and winds of energetic particles. XRISM’s observations provide the first direct evidence of this energy injection stirring up the gas in the cluster core, creating localized turbulence.
This energy injection has significant implications for understanding star formation in galaxy clusters. Star formation requires cold gas, but the energy released by the black hole heats the surrounding gas, making it more difficult for stars to form. This suggests that supermassive black holes play a crucial role in regulating star formation and influencing the evolution of galaxies.
“XRISM allows us to unambiguously distinguish gas motions powered by the black hole from those driven by other cosmic processes, which has previously been impossible to do,” said Congyao Zhang, a former University of Chicago postdoctoral researcher, currently at Masaryk University, who co-led the study.
By mapping the gas motions within galaxy clusters, XRISM is providing new insights into the roles of dark matter and supermassive black holes in shaping the evolution of the universe. The satellite’s observations represent a significant step forward in our understanding of these complex and dynamic environments.
