DATE2025.05.16 #News
Bullet-like ionized clumps shooting out from a quasar at relativistic speeds
Summary of Presentation
Supermassive black holes lie at the centers of all galaxies and are believed to evolve along with their host galaxies—a process known as “galaxy–black hole coevolution.” Understanding this intricate relationship remains one of the most compelling challenges in astrophysics. A central player in this process is the “wind” or “outflow” of gas that black holes eject at high speeds. These outflows are thought to regulate star formation by heating or expelling the surrounding gas, thereby shaping the growth of both the galaxy and the black hole.
To truly understand the impact of the wind, astronomers must precisely measure the motion and energy of the outflowing gas. However, until now, existing instruments lacked the resolution and sensitivity to uncover the finer details.
In this study, an international team led by Dr. Kouichi Hagino, an assistant professor in the Graduate School of Science at the University of Tokyo (the XRISM Collaboration, hereinafter referred to as the “research team”) observed winds traveling at 20–30% of the speed of light from a supermassive black hole. These observations were performed with the X-ray Imaging and Spectroscopy Mission (XRISM), a JAXA-led international space telescope to perform high resolution observations of X-rays emitted by very hot gas. For the first time, the research team revealed that these winds are not smooth but made up of at least five distinct gas components, each moving at different velocities. This indicates a complicated clumpy wind structure resembling a rapid-fire stream of gas “bullets.” Such a breakthrough was only possible thanks to XRISM’s exceptional capabilities in resolving the velocity structure of the winds.
By accounting for this bullet-like structure, the research team estimated that the black hole expels gas at a rate of 60 to 300 solar masses per year. The energy carried by these winds is over 1,000 times greater than that of galactic-scale winds*1, dramatically altering our understanding of their role.
These findings suggest that gas is being intermittently ejected like a geyser or channeled through gaps in the surrounding interstellar medium, challenging long-standing theories of galaxy–black hole coevolution. Continued observations with XRISM promise to deepen our understanding of how these powerful winds influence the “galaxy-black hole coevolution”.
This result has been published in the British scientific journal Nature.
Figure: Artist’s impression of the supermassive black hole PDS 456. High-speed winds—illustrated in white—are being ejected from the vicinity of the black hole. (Credit: JAXA)
Related Links
Journals
-
Journal Name NatureTitle of paper Structured ionized winds shooting out from a quasar at relativistic speeds