1. Quasars

2. Distant Light
Some objects in deep space are visible, small, and have large redshifts.
Very distant by Hubble’s law
Billions of light years away
larger wavelength
nearby galaxy
distant object

3. Quasi-Stellar Objects
These objects were first observed as intense radio sources.
Bright, but star-sized
They were named quasi-stellar radio sources—quasars.
Quasars emit in all parts of the electromagnetic spectrum.
100 times Andromeda
Brighter flares
3C279, a quasar photographed in gamma rays

4. Distant Past Looking at a faraway object is like looking back in time.
If a quasar is 4 billion ly away, we are seeing the universe 4 billion years ago.
Early life of galaxies
Andromeda — 2 million years ago
Earth
PKS 1127 — 4 billion years ago

5. Disk and Jets Radio measurements show two giant jets of radiating gas.
Visible light and x-rays see a disk of gas, dust and stars.
Most intense at center

6. Jet Formation Quasars form from a supermassive black hole.
The black hole draws stars and dust to its center.
The material is accelerated to high velocity and ejected out either side.

7. Active Nuclei Some nearby galaxies show jets of radiating gas.
Start at galactic black hole
Active from dust falling in
Quasars fade to active galaxies as dust decreases.

8. Radio Galaxies
Visible elliptical galaxies have black holes in their center.
The jets are only seen with radio telescopes.
Radio galaxies
Active spiral galaxies are called Seyfert galaxies.

9. Colliding Black Holes
The Chandra X-ray Observatory has observed two supermassive black holes in the same galaxy.
NGC 6240: 400 Mly
When the holes collide in a few hundred million years, the gravity waves will be felt on earth.