One of the wonders of the universe is an active supermassive black
hole.
A massive, whirling disk and torus of material around a dense, unseen
object that may be billions of times as massive as the Sun. The object is
blazing with light as it swirls down onto the heart of the black hole. How
large do these buildings become, though?In a galaxy known as III Zw 002,
located 1.17 billion light-years distant, the edges of the vast accretion
disk encircling a supermassive black hole hundreds of millions of times the
mass of our Sun have been clearly detected for the first time.
The accretion disk may be seen out to around 52 light-days from the black
hole thanks to these discoveries, which were made under the direction of
astronomer Denimara Dias dos Santos of the Brazilian National Institute for
Space Research. This measurement will help us understand the mechanism of
feeding huge black holes better.
Reconstructing the material surrounding a black hole is a challenging task.
Despite their size and the dazzling surrounding material, they are still too
tiny for us to discern much detail in due to the distances between us and
their galaxy.
Since it is impossible to photograph the material directly, light from the
galaxy it surrounds is examined for certain signs that point to the
existence of an accretion disk.
The so-called double peak in the
emission
spectrum is one of such indicators. Rotation is what causes this to happen.
When an excited atom loses energy, it emits light, the wavelength of which
varies depending on the atom's element. This glow is known as
emission.
Think of an accretion disk surrounding a black hole as a record on a
turntable with this in mind. There is a disk that is travelling away from
you and a disk that is coming towards you. Light is pushed by the portion of
the disk travelling in our direction, shortening its wavelengths, while
light is stretched by the portion moving away from us.
This indicates that a particular element's emission manifests at two
wavelengths, creating a double peak in the spectrum.
Prior detections of double peaks surrounding supermassive black holes have
come from a location called the narrow-line area, which is
comparatively near
to the black hole. This provides only limited information about the
accretion disk's whole extent.
Two double peaks were discovered by Dias dos Santos and her associates;
they were located in the wide line section of the accretion disk, which is
located considerably further out from the black hole than the narrow line
zone.
This is the first time that twin peaks have been found in the wide line
area and with a near-infrared sensor.
Scientist Alberto Rodriguez-Ardila
of the National Astrophysics Laboratory in Brazil states, "For the first
time, the detection of such double peaked profiles puts firm constraints on
the geometry of a region that is otherwise not possible to resolve."
"And we now possess convincing proof of an active galaxy's inner structure
and feeding mechanism."
Hydrogen was the first double peak to emerge from the inner portion of the
wide line. According to modeling, this was 16.77 light-days away from the
black hole.
The second, an oxygen detection, came from the periphery of the area,
around 18.86 light-days away from the black hole. Additionally, the modeling
indicates that the wide line zone is located 52.43 light-days away from the
black hole.
9,078
astronomical units are that. Pluto is located 40 astronomical units from the Sun, to put that
into perspective.
That seems enormous, and it is, but it is in line with efforts to quantify
the size of accretion disks by measuring light echoes that reflect off the
inner rim of the torus; the researchers
refer
to this size as "compact" in their work.
The group will keep an eye on the galaxy to determine if its current
behavior conforms to their forecasts.
"This finding sheds light on the fascinating phenomena occurring around
supermassive black holes in active galaxies and gives us valuable insights
into the structure and behavior of the broad line region in this particular
galaxy,"
adds Rodriguez-Ardila.
The research has been published in
The Astrophysical Journal Letters.
