MIT scientists have converted the echoes of a black hole into sounds to reconstruct what is happening in the surroundings of these astronomical phenomena.
A new automated search tool, coined the ” Reverberation Machine, ” has discovered eight new echoing black hole binaries in our galaxy.
Previously, only two such systems in the Milky Way were known to emit X-ray echoes .
In a study appearing in the Astrophysical Journal, MIT researchers present video simulations of light echoes from the accretion disk around a maximally rotating (“Kerr”) black hole .
The white circle indicates the location of the black hole ‘s event horizon , and the light echoes are color-coded according to their observed frequency, which can be distorted by Doppler shifts and by the black hole ‘s strong gravity . The simulation has been sonified in such a way that lower frequency light corresponds to lower pitch sound.
Sounds for black hole studies
By comparing the echoes between systems, the team has built a general picture of how a black hole evolves during an outburst. In all systems, they observed that a black hole first goes through a “hard” state, generating a corona of high-energy photons along with a jet of relativistic particles that are launched at close to the speed of light. The researchers found that at a certain point, the black hole emits a final high-energy flash , before transitioning into a “soft” low-energy state.
This final flash may be a sign that a black hole ‘s corona , the region of high-energy plasma just outside a black hole ‘s boundary , is briefly expanding, ejecting a final burst of high-energy particles before disappearing entirely. . These findings could help explain how the largest supermassive black holes at the center of a galaxy can eject particles across vast cosmic scales to shape galaxy formation.
“The role of black holes in the evolution of galaxies is an outstanding question in modern astrophysics,” says Erin Kara, assistant professor of physics at MIT, in a statement. “Interestingly, these black hole binaries appear to be ‘mini’ supermassive black holes, and so by understanding the outbursts in these small nearby systems, we can understand how similar outbursts in supermassive black holes affect the galaxies in which they live .” reside”. (EuropePress)
