Monday 26 March 2012

Few Facts About QUASARS

Quasar Facts

1. Definition of a Quasar: A Quasar is the bright centre of a young galaxy believed to be powered by mass falling into a supermassive black hole.
2. Mass: 106 to 109 solar masses (2x1036 to 2x1039 kg, or 4.4x1036 to 4.4x1039 Lbs)
3. Observed Distances: 1.5 billion to 28 billion light years (1.4x1025 to 2.6x1026 km, or 8.7x1024 to 1.6x1026 miles)
4. Observed redshifts: 0.06 to 6.43
5. Average Luminosity: 1040 W OR 1047 ergs/s
6. Speed: about 150,000 km/s OR 93,200 miles/s (half the speed of light)
Artist's Impression of a Quasar
click to enlarge
7. Brightest quasar in the sky: 3C-273 (apparent magnitude 12.8) 8. Closest quasar discovered: PKS2349 (1500 million light years away from Earth = 1.4x1025 km, or 8.7x1024 miles)
9. Most distant quasar discovered: CFHQS J2329-0301 (2.6x1026 km, or 1.6x1026 miles)
10. No. of quasars discovered: about 100,000

Timeline History

Late 1950s: The first quasar was discovered.
1960: By this time, hundreds of quasars were discovered and featured in the Third Cambridge Catalogue.
1962: It was found that object 3C-273 was moving away from us at 47,000 km/s (29,200 miles/s).
1964: Hong-Yee Chiu, a Chinese born US astrophysicist, coined the term quasar in Physics Today to describe such objects.
1979: The magnificent gravitational lensing effect predicted by The General Theory of Relativity, given by Einstien, was verified with images of double quasar 0957+561.
1998: The hyperluminous quasar APM 08279+5255, with an absolute magnitude of -32.2 was discovered.

Interesting Facts

Quasar 3C-273
click to enlarge
1. The largest known quasars burn out masses equivalent to 1000 Suns every year to produce a huge amount energy. This amounts to eating up 600 Earths every day. 2. Some quasars have been found to move at speeds of about 93% the speed of light.
3. It is believed that most galaxies are quasars in the initial stages of their life. As the amount of matter falling into the central supermassive blackhole reduces, the energy output reduces and quasars become ordinary galaxies.
APM 08279+5255 is a quasar in the constellation Lynx,[1] that is notable for being a particularly good example of a gravitational lens. When originally discovered, the combination of its high redshift and brightness (particularly in the infrared) made it the most luminous object known- the light left the quasar more than 12 billion years ago (it is 12 billion light-years from Earth). High-resolution observations with the NICMOS camera on-board the Hubble Space Telescope revealed that the source was actually composed of three discrete components, with a maximum separation of 0.4 arcsec. Subsequent observations with the STIS spectrograph (also aboard HST) showed that each component has the same spectral energy distribution and therefore that each is probably an image of a single quasar. The lensing hypothesis greatly reduces the intrinsic luminosity of the lensed quasar as the observed brightness is enhanced by the magnification effect of the lens. Gravitational lens systems with odd numbers of images are extremely rare, most containing two or four.
In 2011 it was reported that vast amounts of water vapor in a cloud-like phenomenon are around this quasar, the oldest and largest mass of water in the known universe- 140 trillion times more water than that held in all of Earth's oceans combined. Its discovery shows that water has been prevalent in the known universe for nearly its entire existence- to 1.6 billion years after the Big Bang, 1 billion years earlier than any previous discovery.[2][3]

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