Using the Event Horizon Telescope, astronomers have captured an image of a quasar (bright structure at the galaxies’ cores) at the Centre of a faraway galaxy that emits vast amounts of light fueled by a feeding supermassive black hole.
Such stunning phenomena, which can generate more energy than all the stars in their parent galaxy put together, are commonly referred to as the “central engines” of active galaxies. Nonetheless, the science behind their strong behavior is still remain unclear by scientists.
Observing NRAO 530:
The Event Horizon Telescope (EHT) recently took an image of a quasar at the centre of the galaxy NRAO 530. The EHT is well known for capturing the first image of a black hole in 2019. In May 2022, the EHT collaboration team will take an image of Sagittarius A (Sgr A), the supermassive black hole at the centre of our own Milky Way galaxy, as a follow-up to their image of the supermassive black hole at the centre of galaxy Messier 87 (M87).
But, the recently reported observation is unique since it was made in April 2017 while the space-based telescope was viewing NRAO 530 to calibrate in advance of observing the black hole at the centre of our galaxy.
“It’s also the most distant object that we have imaged with the EHT so far,”
Maciek Wielgus, a scientist at the Planck Institute for Radio Astronomy and member of the EHT collaboration team, issued the following statement: “The light that we see traveled toward Earth for 7.5 billion years through the expanding universe, but with the power of the Event Horizon Telescope we see the details of the source structure on a scale as small as a single light-year.”
Black holes brighten their galaxies:
It may seem odd that black holes can fuel such a bright spectacle. They absorb light behind an event horizon. The strong gravitational pull from central black holes accelerates material to near-light speed. Quasars generate radiation by heating material. Black holes can be millions or billions of times more massive than the sun. As a result, quasars experience a dramatic increase in brightness, however, this isn’t their only source of radiation.
These black holes absorb their surroundings, but not everything is sucked into their vortex and out through the event horizon. Particles in quasars are similarly guided to the poles of their supermassive black holes by magnetic fields. From this point, the particles are accelerated to nearly the speed of light and collimated into brilliant, narrow jets. From quasars, these jets may extend for tens of thousands of years. The formation of these jets in the magnetic fields of quasars is a mystery.
The EHT analysis of NRAO 530:
The central quasar of NRAO 530 is also known as a blazar, a type of quasar whose radially jets are clearly aimed towards our planet.
The Event Horizon Telescope analyzed this quasar in polarized and unpolarized light to study the magnetic field structure near the black hole and the deepest region of the jet. This showed a brilliant spot on the jet’s southern end that is linked to its core.
The brightness of this core’s substructure shows that the magnetic field exceeds the jet’s energy.
The jet also has two right-angled and parallel characteristics. The team concluded the jet’s magnetic field is helical.
“The outermost feature has a particularly high degree of linear polarization, suggestive of a very well-ordered magnetic field,” Svetlana Jorstad, a senior scientist at Boston University and member of the EHT collaboration team, made the claim.
The quasar will be studied further by the Event Horizon Telescope team. The purpose is to learn more about the evolution of the innermost jet features. They also want to understand the relation of the jet features to the generation of high-energy photons.