The Current Status of Hypervelocity Stars Galactic Center Workshop Shanghai 2009 Oct 21 Warren R. Brown Smithsonian – CfA Collaborators: Margaret Geller, Scott Kenyon
+850 km/s (!!) The First Hypervelocity Star
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)
Latest Results Brown et al (2009a)
Links to Dark Matter Brown et al. (2009b)
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...
Runaway B Stars HVSs Binary disruption: 1.Supernova 2.Dynamical Runaways Bromley, Kenyon, Brown & Geller (2009)
Runaway vs. HVS Bromley, Kenyon, Brown & Geller (2009) Brown et al. (2009b)
Conclusions 1. = 2. NY Times