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Researchers have developed a method for analyzing gravitational waves that allows them to trace the origin and formation history of black holes based on changes in their rotation speed. This approach opens up new possibilities for studying the evolution of black holes, including supermassive ones.
By analyzing gravitational waves from 69 black hole merger events, scientists have found that the rotation of these objects changes after reaching a certain mass. As Isobel Romero-Shaw of the University of Cambridge explains, such behavior is typical of black holes formed by successive mergers in dense star clusters. Gravitational waves recorded by detectors LIGO and Virgo, reflect this process: the intensity of the waves increases before merging, taking away some of the kinetic energy of the system.
The study found that when a black hole reaches a certain mass threshold, its rotation speed changes systematically. This threshold is consistent with formation models that indicate multiple collisions of black holes in densely populated clusters. This provides a unique “signature” to identify objects of this origin, distinguishing them from black holes that formed under other conditions.
Fabio Antonini, the study's lead author, says the method allows us to distinguish between black holes of different origins, improving computer models of their formation. This is particularly important for studying supermassive black holes that could not have arisen from the collapse of stars, but rather from a series of mergers.
This discovery not only deepens our understanding of the evolution of black holes, but also creates a basis for interpreting future observations of gravitational waves, which will contribute to the development of astrophysics and cosmology.
