1. More than just a candy bar.
The Milky Way
More than just a candy bar.

3. Goals Structure of our Galaxy. Its size and shape.
How do stars and things move through it?
The Galactic Center.
How does the Milky Way compare to other galaxies?

4. The Milky Way Stars Dust Gaseous Nebulae Open Clusters
Globular Clusters
Pulsars
Black Holes
How do they all fit together to make our galaxy?

5. Optical emission from stars and nebulae

6. Near-Infrared emission from stars – copyright E. L. Wright and COBE

7. Far-Infrared dust emission – copyright E. L. Wright and COBE

8. Radio emission from neutral hydrogen – copyright J. Dickey

9. Near-Infrared stellar emission – copyright E. L. Wright and COBE

10. John P. Gleason
M51 - Copyright HST

11. Where are We? Not at the center of the Milky Way. Where is the center?
Globular Clusters point the way.
M10 – copyright Credner and Kohle

12. You Are Here

13. Concept Test
If the Earth were located at the center of the galaxy, we would see:
Globular clusters in only one direction.
Globular clusters in all directions.
Many more supernovae than we do now.
Many more stars being formed than we do now.
None of the above.

14. 30 kpc
8.0 kpc
1 kpc

15. The Sun’s “age” We define our age by trips around the Sun.
How many trips of Sun around Milky Way?
R = 8.5 kpc
V = 220km/s
P = 2.5x108 yrs
20 trips. R V

16. The Heart of the Galaxy
Because of all the dust in the Galaxy, we can’t see its center in visible light.
Can use IR and radio to pierce the dust.

17. 200 pc
5 pc
Sagittarius A* - Sgr A*

18. Supermassive Black Hole
Infrared images of stars in the Galactic Center over 8 years.
The “+” is the radio source Sgr A*
Conclusion: Must be over one million solar masses within less than 1/5 of a light year!
Event Horizon ~ 0.02 AU!
D = / kpc.
Copyright Eckart & Genzel

19. Copyright – FORS1 VLTI, European Southern Observatory

20. Hubble Tuning Fork

21. Ellipticals

22. Ellipticals Huge No gas. No dust. No young stars.
Nothing but old stars.
Random orbits.

23. M 87 Copyright – Anglo-Australian Telescope Board
Copyright - HST

24. Hubble Tuning Fork

25. Copyright – Adam Block, KPNO

26. Spirals

27. Spirals Like Milky Way. Disks and bulge. Young stars and old.
Gas and dust.
Stars forming.
Stars dying.
M81 and M82 – Copyright R. Gendler

28. M63 Copyright – S. Miyazaki, Suburu

29. NGC1365 Copyright – VLT

30. M33 – Copyright NOAO

31. John P. Gleason
M51 - Copyright HST

32. NGC 4314

33. NGC 891 – Copyright WIYN
NGC 891 – Copyright J.C. Barentine, NOAO

34. Sombrero Galaxy – Copyright P. Barthel VLT
M10 – copyright Credner and Kohle
Sombrero Galaxy – Copyright P. Barthel VLT

35. NGC 4526

36. Irregulars

37. Homework #16
For Wednesday:
Read: Bennett Ch12
Do Quiz 12