An international team of astronomers has recently made a groundbreaking discovery using the European Southern Observatory’s Very Large Telescope (ESO’s VLT). The team found the most distant ‘Radio-Loud’ Quasar, which has sparked a significant amount of interest and discussion within the scientific community.
Understanding Quasars
Quasars are incredibly luminous objects located in distant galaxies that emit jets at radio frequencies. They got their name, short for “quasi-stellar radio source”, in the 1960s when they were first detected. Today, we know that most quasars have faint radio emissions.
Quasars not only emit radio waves and visible light but also ultraviolet rays, infrared waves, X-rays, and gamma-rays. Remarkably large, with widths nearing 1 kiloparsec, most quasars outsize our solar system. These bright discs are found only in galaxies that host supermassive black holes.
Black Holes and Quasars: Understanding Their Connection
A black hole refers to a particular point in space where matter is so dense that it produces a gravitational field so strong that even light can’t escape. The centre of most active galaxies contains a supermassive black hole that draws in surrounding objects. Quasars are formed by the energy released by the swirling material around a black hole just before it’s consumed.
Quasars are categorized into two groups: the “radio-loud” and the “radio-quiet”. The former, comprising about 10% of all quasars, have powerful jets and strong radio-wavelength emissions. The latter, making up 90% of all quasars, lack potent jets and emit weaker radio emissions.
The Discovery of Quasar P172+18
The recently discovered quasar, named P172+18, emits wavelengths with a redshift of 6.8, signifying its light took 13 billion years to reach Earth. Observing this quasar is like looking back in time, providing a glimpse into the universe when it was just around 780 million years old.
P172+18, with a glowing disc around a black hole that is 300 million times more massive than our Sun, is one of the fastest accreting quasars, rapidly accumulating objects from its galaxy. It is only the fourth ‘radio-loud’ source discovered with a redshift greater than six. The higher the redshift, the further away the source is located.
This newly-discovered quasar plays an essential role in our understanding of supermassive black holes. Studying these ‘radio-loud’ super bright objects can lead astronomers to unravel how these black holes grew so sizeable at such a rapid pace after the Big Bang. Moreover, they may provide insight into ancient star systems and astronomical bodies.
About ESO’s VLT
The ESO’s VLT, responsible for observing P172+18, is situated at the Paranal Observatory in the Atacama Desert. Its four Unit Telescopes, boasting 8.2-meter (27 feet) mirrors, can detect objects that are 4 billion times fainter than what can be seen with the naked eye. The European Southern Observatory has declared the VLT as the world’s most advanced optical telescope.
Understanding Redshift
Gravitational redshift occurs when particles of light (photons) struggle to escape a gravitational well, like a black hole. This process expands the light’s wavelength, shifting it towards the red part of the light spectrum. As these photons must move at a constant speed – the speed of light – they lose energy, causing a shift towards the redder part of the light spectrum.
Last Modified: February 11, 2024