A group of researchers analyzed a supermassive black hole with a disk of material that whirls around it “so close that the speed and intensity of the gravitational force influence the way in which the photons of light appear,” as Stefano Bianchi, the first author of the study, states.
The black hole, which has a mass of about 250 million times that of the sun, is located in the center of a galaxy distant from us 130 million light-years and called NGC 3147. According to the astronomers who are studying it, the presence of a disk so close to the black hole event horizon could offer “a unique opportunity to test Albert Einstein’s theories of relativity.”
The peculiarity of this black hole lies in the fact that it does not have enough “food” to be swallowed around itself: the material disk is therefore so thin that it contracts and then swells like a donut instead of becoming flattened.
Previously it was thought that below a certain level of brightness, the accretion disk can no longer exist, as Ari Laor, of the Technion Technological Institute, Israel explains: “What we saw was something completely unexpected, we found the moving gas that produces characteristics that we can explain only as produced by the material that rotates in a thin disk very close to the black hole.”
According to Bianchi, it is a type of record that was expected to be seen only in objects that are 1000 or even 100,000 times brighter. It follows that current theories concerning the patterns of these accretion disks around black holes must be partly revised.
The other interesting feature of the observations, carried out with the Hubble space telescope, are related to the fact that the gas is so directly connected to the gravitational well of the black hole, being very close to it, that its light has difficulty in propagating and therefore it can only be intercepted at wavelengths closer to red.
The study appeared in Monthly Notices of the Royal Astronomical Society.