1. Announcements
Observing Monday-Thursday of this week counts on the third exam.
Fourth exam is Wednesday, November 17
Review will be Monday, November 15

2. Black Holes Observed properties of black holes Eddington luminosity
Accretion disks
Jets
Reading 24.3

3. The light from a quasar is emitted from a region 10 light-days across
The light from a quasar is emitted from a region 10 light-days across. What does this tell us about the quasar?
The brightness will change every day.
The brightness will change every 20 days.
The brightness will not change in less than 10 days.
The brightness will not change in less than 100 days.

4. Accretion disk

5. In Active Galaxies the disk is surrounded by a dusty torus

6. Accretion disks

7. Varieties of Active Galaxies
Radio Galaxies – big jets, no obvious BH
Quasars – jets and BH
Blazars – mainly see the jet

8. Orientation

9. Eddington Luminosity
Limit on the brightness of a black hole

10. Eddington Luminosity

11. Accretion disks
Disks form because infalling matter has angular momentum.
Accretion leads to release of gravitational energy.
Inner regions of disks rotate very rapidly – near the speed of light.
The luminosity of a black hole is limited by its mass.
Accretion disks of solar-mass and supermassive BHs are similar.

12. Jets
| -- Size of our Galaxy -- |

13. Jets

14. Acceleration of a jet

15. Collimation of a jet

16. Superluminal motion

17. What is the lifetime of this jet?
| | = 150,000 light years

18. Evolution of Jets
Jets from active galaxies are large and change slowly
Jets from solar-mass black holes are smaller, by the ratio of the black hole masses, and change more rapidly
It is possible to study the evolution of jets from solar-mass black hole