The Hubble telescope discovers a mysterious black hole disk

Astronomers using the NASA / ESA Hubble Space Telescope have observed a thin and unexpected disc of material surrounding a supermassive black hole at the heart of the spiral galaxy NGC 3147, located 130 million light-years away.

Astronomers are surprised by the presence of the black hole disk in an active galaxy that is so dim. Black holes in certain types of galaxies such as NGC 3147 are considered hungry because the material captured by gravitation does not allow them to be fed regularly. It is therefore curious that a thin disc surrounding a hungry black hole mimics the much larger discs found in extremely active galaxies.

This disk of material surrounding the black hole is of particular interest and offers a unique opportunity to test Albert Einstein's theories of relativity. The disc is so deeply embedded in the intense gravitational field of the black hole that the light of the gas disc is modified, according to these theories, offering astronomers a unique insight into the dynamic processes close to the black hole.

"We have never seen the effects of both general relativity and special relativity on visible light," said Marco Chiaberge, member of the AURA team for ESA, STScI and Johns Hopkins University. .

Hubble measured that the disc material revolved around the black hole at more than 10% of the speed of light. At such extreme speeds, the gas seems to lighten as it goes to Earth on one side and attenuates as it goes on. he is moving away from our planet from the other. This effect is known as the relativistic beam. Hubble's observations also show that the gas is buried so deep in a gravitational well that the light is struggling to escape, and thus appears stretched at wavelengths that are more red. The mass of the black hole is about 250 million times that of the Sun.

"It's an intriguing overview of a record very close to a black hole, so narrow that the velocities and intensity of the gravitational force affect the way we see the photons of light," said the first author of the study, Stefano Bianchi, of the Università. degli Studi Roma Tre in Italy.

Artist, printing the particularly thin disc of material surrounding a supermassive black hole in the heart of the spiral galaxy NGC 3147, located 130 million light-years away. Credit: ESA / Hubble, Mr Kornmesser

In order to study the matter that is swirling deep inside this disc, the researchers used the Hubble Space Telescope Imaging Spectrometer Instrument (STIS). This diagnostic tool divides the light of an object into its many wavelengths to determine the speed, temperature, and other characteristics of the object with great precision. STIS was an integral part of effectively observing the low-light region around the black hole, blocking the bright light of the galaxy.

Astronomers initially chose this galaxy to validate the accepted models for active galaxies of lower luminosity: those with malnourished black holes. These models predict that material disks should form when large amounts of gas are trapped by the gravitational pull force of a black hole, then emitting a lot of light and producing a shiny beacon called quasar.

View from top to bottom of an artist's imprint on the particularly thin disk of material surrounding a supermassive black hole in the heart of the spiral galaxy NGC 3147, located 130 million light years away. Credit: ESA / Hubble, Mr Kornmesser

"The type of record we see is a reduced quasar that we did not expect to exist," said Bianchi. "It's the same type of disc that we see in 1000, or even 100,000 times brighter objects. Predictions of current models for very weak active galaxies have clearly failed. "

The team hopes to use Hubble to search for other very compact discs around low-light black holes in similar active galaxies.

Publication: Stefano Bianchi, et al., "HST unveils a compact, relatively relativistic, enlarged region, in the real type 2 candidate, NGC 3147," MNRAS, 2019; doi: 10.1093 / mnrasl / slz080