Using observations from state-of-the-art technology, the team of researchers led by the University of Southampton- found evidence that a stellar-mass black hole in our galaxy (known as 4U 1630-472) is rotating rapidly around its axis. This discovery enlightens the characteristics of black holes and the environment surrounding them.
The black hole found to be rotating around its axis while sucking in falling material. It is liable to gravitational stresses and temperatures so high that it starts to sparkle brilliantly in X-rays, which were seen by stargazers utilizing telescopes.
Einstein’s General Theory of Relativity (GR) suggests that in the event that a black hole is rotating rapidly, it will modify the existence around it in a way which is not quite the same as that for a black hole which isn’t rotating.
Such modifications from high spin rates leave an impression on the shape of the radiation from the material rotating very close to the black hole before disappearing. Therefore, if the change in shape of the emitting spectra can be determined somehow, then the GR can be used to measure the black hole spin.
Dr. Mayukh Pahari, from the University of Southampton and lead author, said: “Detecting signatures that allow us to measure spin is extremely difficult. The signature is embedded in the spectral information which is very specific to the rate at which matter falls into the black hole. The spectra, however, are often very complex mostly due to the radiation from the environment around the black hole.
“During our observations, we were lucky enough to obtain a spectrum directly from the radiation of the matter falling into the black hole and simple enough to measure the distortion caused by the rotating black hole.”
The study, funded by the Royal Society and published in the Astrophysical Journal.