1. The Milky Way

2. Structure of the Milky Way

4. The Milky Way

5. Components of the Milky Way Disk  Population I stars  Open clusters  HII regions Bulge  Population II stars Halo  Globular clusters

6. Omega Centauri

7. Stellar Populations M100

8. Finding Our Place Sun Early view Sun at center Harlow Shapley Globular Clusters evenly distributed Globular Clusters unevenly distributed

9. Mapping the Galaxy Visible Light  Strong interstellar absorption  We can see only 4000 - 5000 pcs Radio Light  Can observe entire galaxy

10. 21-cm Radiation Proton Electron

11. Mapping the Galaxy H clouds in different spiral arms will have different Doppler Shifts Sun Wavelength

12. 21-cm Data

13. Galactic Rotation Curve

14. Observed Rotation Curve Keplerian Orbits

15. Dark Matter Halo

16. Dark Matter There must be significant amount of mass in the Galaxy in an underluminous form (perhaps as much as 90% of total)  Compact Objects - White Dwarf, Neutron Stars, Black Holes qMACHO’s - MAssive Compact Halo Objects  Planets, Brown Dwarfs  WIMP’s qWeakly Interacting Massive Particles