TAG: GS 3: SCIENCE AND TECHNOLOGY
THE CONTEXT: Astronomers have discovered the brightest quasar ever observed, named J0529-4351, using European Southern Observatory’s (ESO) Very Large Telescope (VLT).
EXPLANATION:
Discovery of Quasar
- Using the European Southern Observatory’s (ESO) Very Large Telescope (VLT), astronomers found the bright quasar which is said to be the most luminous object ever observed.
- Scientists have discovered the fastest-growing black hole known to date.
- It has a mass of 17 billion Suns and eats just over a Sun per day.
- This makes it the most luminous object in the known Universe.
Quasars
- Quasars are the glowing cores of distant galaxies powered by supermassive black holes.
- The word quasar is short for “Quasi-stellar Radio Source”.
- Quasars are the active galactic nuclei (bright cores of distant galaxies).
- Despite their brightness, due to their great distance from Earth, no quasars can be seen with an unaided eye.
- They emit radio waves, visible light, UV rays, infrared waves, X-rays, and gamma-rays.
- These black holes accumulate matter from their surroundings, emitting vast amounts of light in the process.
- Consequently, quasars are some of the brightest objects in the sky, visible even from great distances.
- Generally, the most luminous quasars indicate the fastest-growing supermassive black holes.
- However, finding quasars requires precise observational data from large areas of the sky.
- The massive datasets involved often necessitate the use of machine-learning models to differentiate quasars from other celestial objects.
- However, these models are trained on existing data, which limits their ability to identify new, more luminous quasars.
- A new quasar of unprecedented luminosity might be misclassified as a star not far from Earth.
The Discovery of J0529-4351
- An automated analysis of data from the European Space Agency’s Gaia satellite initially misclassified J0529-4351 as a star due to its brightness.
- Researchers at ANU eventually identified it as a distant quasar last year using observations from the ANU 2.3-meter telescope at the Siding Spring Observatory in Australia.
- Identifying it as the most luminous quasar ever observed required more precise measurements, which were obtained using the X-shooter spectrograph on ESO’s VLT in the Chilean Atacama Desert.
- It is 500 trillion times brighter than the Sun
- The quasar, named J0529-4351, is located so far from Earth that its light took over 12 billion years to reach us.
- The matter being pulled in toward this black hole forms a disc that emits so much energy that the quasar is over 500 trillion times more luminous than the Sun.
- All this light comes from a hot accretion disc that measures seven light-years in diameter, this must be the largest accretion disc in the Universe.
- To put that in perspective, seven light-years is about 15,000 times the distance from the Sun to the orbit of Neptune.
- Remarkably, this quasar had been hiding in plain sight.
- The object appeared in images from the ESO Schmidt Southern Sky Survey dating back to 1980, but it was only recognized as a quasar decades later.
- Studying distant supermassive black holes can provide important insights into the early universe, including the formation and evolution of these black holes and their host galaxies.
Black Hole:
- Black holes are points in space that are so dense they create deep gravity sinks. Beyond a certain region, not even light can escape the powerful tug of a black hole’s gravity.
- In other words, Black holes are regions in space where an enormous amount of mass is packed into a tiny volume.
Galaxy:
- Galaxies consist of stars, planets, and vast clouds of gas and dust, all bound together by gravity. The largest contain trillions of stars and can be more than a million light-years across.
- The smallest can contain a few thousand stars and span just a few hundred light-years. Most large galaxies have supermassive black holes at their centers, some with billions of times the Sun’s mass.
- Galaxies come in a variety of shapes, mostly spirals and ellipticals, as well as those with less orderly appearances, usually dubbed irregular.
- Most galaxies are between 10 billion and 13.6 billion years old. Some are almost as old as the universe itself, which formed around 13.8 billion years ago. Astronomers think the youngest known galaxy formed approximately 500 million years ago.