Quasar | UPSC

Quasar mind map
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Astronomers find universe's brightest object
Black hole devouring a sun a day
Brightest known object in universe discovered
Hiding in plain sight for decades
Universe's hungriest black hole
Powers the brightest light in space
Universe’s brightest object
Quasar fueled by huge black hole
When
Discovered in 1963
Peak epoch 10 billion years ago
Why
Powered by gas spiraling into supermassive black holes
What
Extremely luminous active galactic nucleus (AGN)
Also known as quasi-stellar object (QSO)
Emission powered by supermassive black hole
Millions to tens of billions of solar masses
Surrounded by gaseous accretion disc
Energy release
Electromagnetic radiation across spectrum
Luminosities thousands of times greater than Milky Way
Redshifts of cosmological origin
Where
Centers of galaxies
Nearest known quasar
About 600 million light-years from Earth
Most distant known quasar
Over 13 billion years ago
Who
Hong-Yee Chiu coined term "quasar"
Key people
Allan Sandage
Margaret Burbidge
Maarten Schmidt
Halton Christian Arp
How
Gas spirals around, heats up, emitting radiation
Visible and ultraviolet light from glowing disk
X-ray energies from hot gas above disk
Jets emit radio waves to X-rays
Dust and gas glow at infrared wavelengths
Significance
Outshine all stars in their galaxies
Visible even at billions of light-years
Help understand early universe
Challenges
Difficult to resolve structures within quasar
Details up for debate, picture may change
Way Forward
Continued observation and research
Hubble Space Telescope
James Webb Space Telescope

Quasars are extremely luminous objects found in the centers of some galaxies, powered by gas spiraling at high velocity into enormous black holes. They can outshine all the stars in their host galaxies, making them visible even from billions of light-years away. Quasars are not only significant for their brightness but also for what they can teach us about the early universe and the formation of galaxies. They were first discovered in the 1960s as quasi-stellar objects due to their star-like appearance and radio emissions. Since then, our understanding of quasars has evolved significantly, thanks to the advancements in astronomical observations and technologies such as the Hubble Space Telescope.