The black holes at the centres of galaxies are the most mysterious objects
in the Universe, not only because of the huge quantities of material within
them, millions of times the mass of the Sun, but because of the incredibly
dense concentration of matter in a volume no bigger than that of our Solar
System. When they capture matter from their surroundings they become active,
and can send out enormous quantities of energy from the capture process,
although it is not easy to detect the black hole during these capture
episodes, which are not frequent.
However, a study led by the researcher Almudena Prieto, of the Instituto de
Astrofísica de Canarias (IAC), has discovered long narrow dust filaments
which surround and feed these black holes in the centres of galaxies, and
which could be the natural cause of the darkening of the centres of many
galaxies when their nuclear black holes are active. The results of this
study have recently been published in the journal Monthly Notices of the
Royal Astronomical Society (MNRAS).
Using images from the Hubble Space Telescope, the Very Large Telescope (VLT)
at the European Southern Observatory (ESO), and the Atacama Large Millimetre
Array (ALMA) in Chile, the scientists have been able to obtain a direct
visualization of the process of nuclear feeding of a black hole in the
galaxy NGC 1566 by these filaments. The combined images show a snapshot in
which one can see how the dust filaments separate, and then go directly
towards the centre of the galaxy, where they circulate and rotate in a
spiral around the black hole before being swallowed by it.
“This group of telescopes has given us a completely new perspective of a
supermassive black hole, thanks to the imaging at high angular resolution
and the panoramic visualization of its surroundings, because it lets us
follow the disappearance of the dust filaments as they fall into the black
hole”, explains Almudena Prieto, the first author on the paper.
The study is the result of the long-term PARSEC project of the IAC, which
aims to understand how supermassive black holes wake up from their long
lives of hibernation, and after a process in which they accrete material
from their surroundings, they become the most powerful objects in the
Universe.
Part of this work was carried out within the Master’s thesis in Astrophysics
of the University of La Laguna of Jakub Nadolny, carried out at the IAC
within the PARSEC project. Researchers Mar Mezcua and Juan A. Fernández
Ontiveros were also advisers to this work, while they had PARSEC
postdoctoral contracts at the IAC.
Reference:
M. Almudena Prieto, Jakub Nadolny, Juan A. Fernández-Ontiveros, Mar Mezcua.
“Dust in the central parsecs of unobscured AGN: more challenges to the
torus”. Monthly Notices of the Royal Astronomical Society, July 8, 2021.
DOI:
https://doi.org/10.1093/mnras/stab1704
Tags:
Space & Astrophysics