QUASARS

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QUASARS

• ( QUASi-stellAR radio source )

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What is a quasar ?

• Extremely bright and distant active nucleus of a
  galaxy.
• First identified to be high redshift sources of
  electromagnetic energy, incl. radio waves and
  visible light, similar to stars.
• A compact halo of matter surrounding a
  supermassive black hole of a young galaxy.

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Discovery of Quasars

• Late 50s and early 60s as radio loud sources
• 1960 the first optical discovery to accompany a
  radio source (radio source 3C 48 was tied to an
  optical object)
• Optical spectrum difficult to interpret, because
  of many before unseen emission and absorbtion
  lines.
• Soon after 1963 it was discovered that the
  strange emission/absorption were just redshited.

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Properties of Quasars

• farther than three billion light-years away the
  most luminous objects in the known universe
• 3C 273 in the constellation of Virgo(from Hubble
  Space Telescope) m12.8, M-26.7
• Its luminosity is about 2 trillion times that of
  our Sun, or about 100 times that of the total
  light of average giant galaxies like our Milky
  Way.

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Properties of Quasars

• Many properties of active galaxies nonthermal
  radiation, jets and lobes like radio galaxies
• Observed in many parts of the electromagnetic
  spectrum including radio, infrared, optical,
  ultraviolet, X-ray and gamma rays

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Some questions connected with Quasars

• How do quasars form and how long does it take?
  Not exactly known how they form it is thought
  that the process begins as gas collects near the
  center of a galaxy, however, it must take
  something like billions years.

• How long do quasars last? Galaxies can only act
  as quasars during the early stages of their
  lives, but this would be for times of billions of
  years.

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Looking at a Quasar is like looking back in time..

• Farther away from Earth than any known object
  in the Universe, it takes billions of years for
  the light they give off to reach Earth. The light
  we see today is what the quasar looked like
  billion of years ago. Some scientist think that
  when they study quasars they study the beginning
  of the Universe.

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http//youtube.com/watch?vqtiK82ZjXLY
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Sources

• http//en.wikipedia.org/wiki/Quasar
• http//www.phys.vt.edu/jhs/faq/quasars.htmlq1
• www.ast.cam.ac.uk/regan/quasars.html
• http//quasars.net.ru/
• http//youtube.com/watch?vqtiK82ZjXLY