NOTES Active Galactic Nuclei AGN QUASARS Radio QuasiStellar

NOTES: Active Galactic Nuclei (AGN) QUASARS: Radio Quasi-Stellar Objects. Maarten Schmidt examined 3 C 273 (3 C=Third Cambridge Catalog of Radio sources) and found its distance from its redshift to be 2 billion light years--not a star, and L = 1040 watts--1, 000 L (MW)!!. 8 to 14(? ) Billion years--distance range. L = 1038 -1042 watts. Energy comes from a region solar system-sized. Radio Jets. A thermal (synchotron) and non-thermal (black-body) continuous spectrum & broad (gas with varying speeds) lines. Found to have stars around them (galaxies) in most cases. Supermassive BH model suggests a billion solar masses by Eddington Limit--Max M(BH) = L /30, 000 (Solar Ms & Ls). If larger mass, luminosity would blow away infalling material. QSO's: Radio quiet Quasi-Stellar Objects. ACTIVE GALAXIES: On average, seen at closer distances than QSOs. Some in nearby clusters. Seyfert Galaxies: ~1037 watts, 1, 000 x dimmer than QSOs. Type I--broad (narrow peak) and narrow emission lines. Type II--just narrow emission lines. ). Radio Galaxies: Less luminous than Quasars. Often elliptical or peculiar (collision-stimulated? ).

3 C 273—first thought To be a strange star. Host galaxy— blocking light from core First discovered Quasar

QUASARS: Quasi-Stellar Radio Objects. Maarten Schmidt examined 3 C 273 (3 C=Third Cambridge Catalog of Radio sources) and found its distance from its redshift to be 2 billion light years--not a star, and L = 1040 watts--1, 000 L (MW)!!

Quasars are the dinosaurs of the cosmos. They went extinct 0. 8 billion years ago, because we don’t see any closer than 0. 8 billion light years.

Quasars: Distance: 8 to 14 Billion years. L = 1038 -1042 watts. Energy comes from a region solar system-sized. Radio Jets. Found to have stars around them (galaxies) in most cases.

Quasars have a thermal (black body) and non-thermal (synchotron) continuous spectrum & broad lines.

Broad vs Narrow lines: material moving in many directions Or orbiting can produce a spread of Doppler Shifts.

Supermassive BH model of quasars suggests a billion solar masses by Eddington Limit--Max M(BH) = L /30, 000 (Solar Ms & Ls). If larger, luminosity would blow away infalling material.

QSO's: Radio quiet Quasi-Stellar Objects. Double QSO 0512 -3329, 0. 64 arcsec separation

Radio Loud vs radio quiet?

In terms of luminosity, Quasars (& QSOs) are the poppa bears, Active Galaxies the momma bears, and Present Day Galaxies like the Milky way are the baby bears. Successively about 1000 x less luminous.

ACTIVE GALAXIES: On average, seen at closer distances than QSOs. Some in nearby clusters. Seyfert Galaxies: ~1037 watts, 1, 000 x dimmer than QSOs. Type I--broad (narrow peak) and narrow emission lines. Type II--just narrow emission lines. ). Radio Galaxies: Less luminous than Quasars. Often elliptical or peculiar (collision-stimulated? ).

Radio Galaxy Centaurus A. Collision of spiral with elliptical?

Blazars: variable quasarlike radio sources, with periods of years --like galactic pulsars. (Exs. BL Lacertae--3 C 279 Burst in 1937 and 1943— 6 year period. )

Unified Model of active galaxies: AGN (Active Galactic Nuclei). In some cases, they may be the same thing seen from different angles.

Naked Quasars: no stars around them --NOT AGN. White Hole? 7 discovered in 1995.