The Discovery of Quasars (the first AGN found) Maartin Schmidt – the ‘discoverer of quasars’ Cyril Hazard – the REAL DEAL

The Cambridge Catalog of Radio Sources A few hundred of the brightest radio sources were compiled with a radio interferometer at Cambridge, England. Unfortunately, the positions were not accurately known. These were the brightest radio sources in the sky – with the exception of the Sun and planets… The brightest was called 3C273.

3C273 could be anywhere in this circle! We needed a better position

Lunar Occultation to the rescue! Must get both entry and exit from the moons limb!!

The Parkes Radio Telescope

3C273

X-ray Radio (VLA)

Schmidt measured the spectrum: Redshift of 0.13 indicating that the object is very far away (about 2.5 billion light years) and very bright!

Radio image of Cygnus A showing a small but very bright radio galaxy in the middle of the 320,000 ly wide lobes

A galaxy lies at the center of double radio sources

Galaxy (which is actually quite large) Intergalactic gas jet Giant Gas Clouds (surrounding the galaxy)

This object that looks like a star must be enormously luminous - its redshift indicates it is 4 billion light years away!!

H b (permitted) O III [5007] (forbidden) O III [4959] (forbidden) Quasars and Seyfert I’s Seyfert II’s

Jet Narrow line region clouds 10 – ly Broad Line Region (Light months) Accretion Disk (light days) Dusty Molecular torus 10 – 1000 ly Black Hole 100 million solar masses

Narrow line region clouds 10 – ly Broad Line Region (Light months) Accretion Disk (light days) Dusty Molecular torus 10 – 1000 ly Black Hole 100 million solar masses

Gas and dust inhibit the jet of particles! Spiral versus Elliptical galaxies

Blazar CD Quasar LD Quasar BLRG NLRG Elliptical Galaxy

BAL QSO QSO (SEYFERT I) FIR GALAXY (SEYFERT II) Spiral Galaxy