On the origins of Hypervelocity stars as revealed by large-scale Galactic surveys
Hypervelocity stars (HVSs) are rare objects of extreme fast velocities allowing them to escape the Milky Way galaxy.
One of the most commonly proposed scenarios is that they originate near the Galactic center (GC) by dynamical interactions between (binary) stars and the central massive black hole(s) (MBH). Alternative explanations exist, for examples, they could be the tidal debris of an accreted and disrupted dwarf galaxy, or they could be surviving companion stars of Type Ia supernovae.
We present a large sample of over ten thousand high velocity stars (HiVels) with total velocity greater than 300 km/s selected from the current large-scale spectroscopic and astrometric surveys.
In this HiVel sample, 43 late-type hypervelocity star (HVS) candidates (32 of them are discovered for the first time) are found with total velocity exceeding their local escape velocities.
With the precise spectroscopic and astrometric information, the origins of those HVSs, as well as HiVels with total velocity greater than 400 km/s, are discussed and found interesting results on the origins of HVSs/HiVels.