heic1913 – Scientific release
July 11, 2019
Astronomers using the NASA / ESA Hubble Space Telescope have observed an unexpected thin disc of matter surrounding a supermassive black hole in 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 general relativity and relativity restricted to visible light with this clarity,"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 look on a record very close to a black hole, so close that the speeds and intensity of gravitational attraction affect the way we see the photons of light,"Explains the first author of the study, Stefano Bianchi, from the Università degli Studi Roma Tre in Italy.
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 several individual wavelengths to determine the speed, temperature, and other characteristics of the object with very high accuracy. 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.
"The type of disc we see is a reduced quasar that we did not expect to exist,"Bianchi explained."This is the same type of disc that we see in 1000 objects, or even 100 000 times brighter. 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.
The Hubble Space Telescope is an international cooperation project between ESA and NASA.
The team's journal will be published in the monthly journal Reviews of the Royal Astronomical Society.
The international team of astronomers participating in this study is Stefano Bianchi (University of Rome, Italy), Robert Antonucci (University of California, Santa Barbara, USA), Alessandro Capetti (INAF – Turin Astronomical Observatory, Italy) ), Marco Chiaberge (Institute of Space Telescope Sciences and Johns Hopkins University, Baltimore, USA), Ari Laor (Israel Institute of Technology, Israel), Loredana Bassani (INAF / IASF Bologna, Italy), Francisco J. Carrera (CSIC – University of Cantabria, Spain)), Fabio La Franca (University of Rome, Italy), Andrea Marinucci (University of Rome, Italy), Giorgio Matt1 (University of Rome, Italy), Riccardo Middei (University Rome) Tre, Italy), Francesca Panessa (Institute of Astrology and Planet Spaziali of INAF, Italy).
Image credit: ESA / Hubble, M. Kornmesser
Dipartimento di Matematica e Fisica, University of Rome, Italy
ESA / Hubble, responsible for public information