Quasar

QUASARS (Quasi-Stellar Radio Source) [QSR]

• Appear like stars
• Emits strong radio signal
• Distant active nuclei of galaxies
• A compact region in the center of a massive galaxy surrounding its central supermassive black hole
• Traveling away from Earth at tremendous speeds (largest Doppler red shifts known)
• First discovered 20 years ago (3C273) by interaction of optical and radio astronomy
• In 1963, Maarteen Schmid discovered a quasar with a 16% Doppler red shift (~3 billion light years away)
• Since then, more than 1,500 quasars discovered with red shifts up to 473%
• Provide information of the early phases of the Universe
• Have been found in a cluster of galaxies (“host galaxies”)

Hubble’s Law: large redshift means large velocities of recession = great distances