1. The Current Status of Hypervelocity Stars Galactic Center Workshop Shanghai 2009 Oct 21 Warren R. Brown Smithsonian – CfA Collaborators: Margaret Geller, Scott Kenyon

2. +850 km/s (!!) The First Hypervelocity Star

3. Links to the Black Hole Ejection Mechanism Observed Properties  Velocity distribution  Spatial distribution  Temporal distribution  Stellar Rotation distribution Single MBH + binary star (Hills 1988) Binary MBH + single star (Yu & Tremaine 2003) Stellar BH + MBH + star (O’Leary & Loeb 2008) (Sesana et al 2007) (Levin 2006) Hansen (2007) Lockmann & Baumgardt (2008) Lopez-Morales & Bonanos (2008)

4. Latest Results Brown et al (2009a)

5. Links to Dark Matter Brown et al. (2009b)

6. HVS = Galactic Center origin 1.There are unbound stars in halo. 2.MBH in the GC. 3.Stars orbit the MBH. 4.HVSs are B stars. 5.GC full of B stars. 6.Travel times < lifetimes. 7.N obs = N predicted. Heber et al (2008) but...

7. Runaway B Stars HVSs Binary disruption: 1.Supernova 2.Dynamical Runaways Bromley, Kenyon, Brown & Geller (2009)

8. Runaway vs. HVS Bromley, Kenyon, Brown & Geller (2009) Brown et al. (2009b)

9. Conclusions 1. = 2. NY Times