Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: MMT Hypervelocity Star Survey   We describe a new survey for unbound hypervelocity stars (HVSs), stars
traveling with such extreme velocities that dynamical ejection from a massive
black hole (MBH) is their most likely origin. We investigate the possible
contribution of unbound runaway stars, and show that the physical properties of
binaries constrain low mass runaways to bound velocities. We measure radial
velocities for HVS candidates with the colors of early A-type and late B-type
stars. We report the discovery of 6 unbound HVSs with velocities and distances
exceeding the conservative escape velocity estimate of Kenyon and
collaborators. We additionally report 4 possibly unbound HVSs with velocities
and distances exceeding the lower escape velocity estimate of Xue and
collaborators. These discoveries increase the number of known HVSs by 60%-100%.
Other survey objects include 19 newly identified z~2.4 quasars. One of the HVSs
may be a horizontal branch star, consistent with the number of evolved HVSs
predicted by Galactic center ejection models. Finding more evolved HVSs will
one day allow a probe of the low-mass regime of HVSs and will constrain the
mass function of stars in the Galactic center.

18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex