Neutron stars: new constraints on asymmetric dark matter
  We study an impact of asymmetric dark matter on properties of the neutron
stars and their ability to reach the two solar masses limit, which allows us to
present a new range of masses of dark matter particles and their fractions
inside the star. Our analysis is based on the observational fact of the
existence of two pulsars reaching this limit and on the theoretically predicted
reduction of the neutron star maximal mass caused by the accumulation of dark
matter in its interior. We also demonstrate that light dark matter particles
with masses below 0.2 GeV can create an extended halo around the neutron star
leading not to decrease, but to increase of its visible gravitational mass. By
using recent results on the spatial distribution of dark matter in the Milky
Way, we present an estimate of its fraction inside the neutron stars located in
the Galaxy center. We show how the detection of a 2 Msun neutron star in the
most central region of the Galaxy will impose an upper constraint on the mass
of dark matter particles of ~ 60 GeV. Future high precision measurements of the
neutron stars maximal mass near the Galactic center, will put a more stringent
constraint on the mass of the dark matter particle. This last result is
particularly important to prepare ongoing, and future radio and x-ray surveys.
