The Milky Way Galaxy

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Stellar streams

Belokurov et al (2007)

Slide 32

Tidal streams (Pal 5)

Sloan digital sky survey (SDSS)

Slide 33

Dark Halo

Hard to track around MW

NGC 3198

Milky Way

Slide 34

Dark halos cuspy?

Slide 35

Gravitational microlensing

Microlensing and magnitude of non-circular motions imply little DM at r<5kpc

Slide 36

Conclude

Halo rather spherical

Counts of gravitational microlensing events imply that its mass is not in stellar or planetary objects

Slide 37

DM Searches

If m~GeV/c2, ~106 /cm2/s at ~300 km/s

Seasonal variation in flux

Slide 38

If particles weakly-interacting, one occasionally impacts atomic nucleus

look for events deep underground (shielded from cosmic rays)

Boulby, Yorks

Slide 39

UKDMF Boulby

Slide 40

Limits on cross section

CDMS Collaboration (06)

SSM

Slide 41

Conclusion

Understanding the Milky Way key for understanding the Universe

Provides probe of constitution of Universe

Much progress in the last decade

Still many unresolved questions

Will remain on the frontier of physics & astronomy for the foreseeable future