We discuss our targeted search for hypervelocity stars ( HVSs ) , stars traveling with velocities so extreme that dynamical ejection from a massive black hole is their only suggested origin .
Our survey , now half complete , has successfully identified a total of four probable HVSs plus a number of other unusual objects .
Here we report the most recently discovered two HVSs : SDSS J110557.45+093439.5 and possibly SDSS J113312.12+010824 , traveling with Galactic rest-frame velocities at least +508 \pm 12 and +418 \pm 10 km s ^ { -1 } , respectively .
The other late B-type objects in our survey are consistent with a population of post-main sequence stars or blue stragglers in the Galactic halo , with mean metallicity [ Fe/H ] _ { W _ { k } } = -1.3 and velocity dispersion 108 \pm 5 km s ^ { -1 } .
Interestingly , the velocity distribution shows a tail of objects with large positive velocities that may be a mix of low-velocity HVSs and high-velocity runaway stars .
Our survey also includes a number of DA white dwarfs with unusually red colors , possibly extremely low mass objects .
Two of our objects are B supergiants in the Leo A dwarf , providing the first spectroscopic evidence for star formation in this dwarf galaxy within the last \sim 30 Myr .