the milky way. structure of the milky way the milky way
TRANSCRIPT
The Milky WayThe Milky Way
Structure of the
Milky Way
The Milky WayThe Milky Way
Components of the Milky Components of the Milky WayWay
• DiskPopulation I starsOpen clustersHII regions
• BulgePopulation II stars
• HaloGlobular clusters
Omega CentauriOmega Centauri
Stellar PopulationsStellar Populations
M100
Finding Our PlaceFinding Our Place
Sun
Early viewSun at center
Harlow Shapley
Globular Clusters evenly distributed
Globular Clusters unevenly distributed
Mapping the GalaxyMapping the Galaxy
• Visible LightStrong interstellar absorptionWe can see only 4000 - 5000 pcs
• Radio LightCan observe entire galaxy
21-cm Radiation21-cm Radiation
Proton
Electron
Mapping the GalaxyMapping the Galaxy
• H clouds in different spiral arms will have different Doppler Shifts
Sun
Wavelength
21-cm Data21-cm Data
Galactic Rotation CurveGalactic Rotation Curve
Observed Rotation CurveObserved Rotation Curve
Keplerian Orbits
Dark Matter HaloDark Matter Halo
Dark MatterDark 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 HolesMACHO’s - MAssive Compact Halo Objects
Planets, Brown DwarfsWIMP’s
Weakly Interacting Massive Particles