Tuesday 18 November 2025
A team of researchers has made significant progress in understanding the mysterious bubbles surrounding ultraluminous X-ray sources (ULXs). These celestial phenomena are thought to be powered by super-Eddington accretion onto neutron stars or black holes, but the exact mechanisms behind their formation and evolution remain unclear.
To shed light on these enigmatic objects, scientists have turned to computer simulations. By modeling the behavior of gas and radiation in 3D, researchers can recreate the environments surrounding ULXs and study the interactions between the central object, the accretion disk, and the surrounding medium.
The latest simulation effort, led by Jiahui Huang and Ken Ohsuga at the University of Tsukuba, has revealed some fascinating insights. By injecting outflows with uniform mass rates and momentum into a conical funnel, the team found that the morphology of the bubble is determined by the initial momentum of the outflows.
In other words, the shape and size of the bubble depend on how fast and powerful the outflows are. This makes sense, given that ULXs are thought to be powered by super-Eddington accretion, which would release a tremendous amount of energy into the surrounding environment.
The researchers also found that the mechanical power of the outflows affects the size of the bubble but not its shape. This suggests that the bubble’s structure is primarily determined by the initial momentum of the outflows rather than their total energy.
Moreover, the study revealed that low mechanical power can lead to a short cooling timescale for the system, causing the bubble shell to collapse earlier than expected. This has important implications for our understanding of ULX evolution and the role of wind-driven bubbles in shaping galaxy evolution.
The team’s results also highlight the importance of considering the viewing angle of the observer when interpreting observations of these objects. By modeling different angles, researchers can better understand how the observed morphology of the bubble relates to its underlying structure.
While there is still much to be learned about ULXs and their bubbles, this study demonstrates the power of computer simulations in advancing our knowledge of these complex phenomena. As researchers continue to refine their models and gather more data, we can expect even more exciting insights into the mysteries of the universe.
Cite this article: “Unlocking the Secrets of Ultraluminous X-ray Sources’ Bubbles”, The Science Archive, 2025.
Ulxs, Bubbles, Accretion, Neutron Stars, Black Holes, Super-Eddington, Outflows, Momentum, Galaxy Evolution, Computer Simulations
